Session Index

Since 2011, our group has been working on the trapping and analysis of proteins with nanoapertures in metal films. This talk will review the technique, recent advances (including tracking proteins, trapping proteins down to 4 kDa, analysis of the impact of mutation), and briefly highlight exciting developments from others in the field.

  Preview abstract

Surface plasmons offer advantageous properties for enhancing light-matter interactions, primarily through their ability to tightly confine light fields. By employing metallic nanoholes as the plasmonic nanocavity and InP nanowires as the gain medium, we have successfully achieved lasing of localized surface plasmons at room temperature, making them highly suitable for communication applications. Additionally, our plasmonic nanolasers demonstrate superior features such as elevated spontaneous emission coupling factors, reduced mode volumes, and decreased power consumption, all attributed to the enhanced interactions between light and matter.

  Preview abstract

We propose high-bandwidth white-light emitting diodes (WLEDs) that combine a single-pixel semipolar (20–21) blue micro-LED, a phenothiazine/dimesitylborane-based organic blue emitter (CC-MP3), green-emitting CH3NH3PbBr3 perovskite quantum dots (PQDs), and a commercially available red-emitting phosphorescent emitter (Ir(fbi)2(acac)) for visible light communication (VLC) and lighting applications. By designing the color conversion layers appropriately, the WLEDs achieved a bandwidth ranging from 952 to 1008 MHz, a CCT ranging from 4000K to 6000K, and a CRI ranging from 61.3 to 82.4. Moreover, PQDs and CC-MP3 were significantly stable in optical and frequency response performance after 180 days of storage.

  Preview abstract

Exceptional points (EPs) are singularities in non-Hermitian systems where eigenvalues and eigenstates merge. This allows for unique control of asymmetric light, limited by EP chirality. Here we introduces a method to extend this control to any polarization by engineering EP pairs. Our plasmonic metasurface features chiral degenerate eigenstates for circular polarization at EPs, resulting in asymmetric reflection for all circular polarizations. Manipulating chiral EP handedness within the metasurface enables control of arbitrary polarizations, overcoming topological metasurface constraints. Furthermore, we utilize EP pairs and rotation-induced phase to create versatile vectorial holographic images, offering innovative wave control possibilities in photonics applications.

  Preview abstract

In this study, tungsten trioxide (WO3) nanorods were grown using hydrothermal synthesis method as the sensing membranes of NO gas sensors. The performance of the NO gas sensors using WO3 nanorod sensing membranes could be improved by annealing in the hydrogen (H2) ambience at 400 oC for 15 min. The optimal responsivity of the NO gas sensor was 2305.2% under NO concentration of 1 ppm and operation temperature of 140 oC.

  Preview abstract

The forward design process could be cumbersome and limited by the human imagination when it comes to exploring complex shapes to achieve optimal performance. However, inverse design allows us to break free from those limitations and design unconventional and simple patterns. In our work, we leverage the power of inverse design to optimize the geometric layout of metagratings, enabling us to achieve higher efficiency compared to conventional forward-designed gratings. We also optimize non-orthogonal polarization pairs and achieve similar results as forward design methods could achieve with orthogonal polarization states, which expand functionality and could further apply to polarization camera.

  Preview abstract

Vector vortex beams (VVBs) have garnered considerable interest owing to their unique polarization properties, opening up new possibilities for innovative applications in optics and communication. There has been a persistent desire to find an effective method for dynamically switching the topological charge of VVBs. In our study, we successfully generate VVBs with topological charge (TC) of +1 and -2 in hexagonal-lattice PCSELs. Moreover, we achieve dynamic modulation of the TC of VVBs by controlling the pulse duration, enabling us to switch between modes with varying TC values.

  Preview abstract

This work emphasizes the utilization of SERS-active Ag nanoprisms with sharp tips and edges on Cu2O microspheres for ultra-sensitive antibiotic detection in real-world samples. The proposed SERS substrate endows superior detection performance, including high sensitivity, high enhancement factor of 2.31×10^11, ultra-low limit of detection of 5.80×10^−13 M, superior uniformity and reproducibility with the RSD < 8.31%.

  Preview abstract

This study presents a novel approach for the detection of Levodopa (L-dopa) using Surface Plasmon Resonance (SPR) combined with Cyclic Voltammetry (CV). The oxidation reaction of the drug L-dopa is conducted on gold nanoholes by applying EC voltage swing. The nanoholes generate surface plasmon resonance (SPR) and the oxidation process is monitored by SPR spectrum. The results showed that the limit of detection (LOD) using traditional CV reached 1.47 μM, while using EC-SPR, the LOD improved to 1.23 μM.

  Preview abstract

Monolayer transition metal dichalcogenides (TMDCs) exhibit ultra-low-threshold excitonic lasers, and optical gain can be achieved near trion emission with lower carrier injection. Therefore, this study aims to utilize the trion emission of monolayer WSe2 as a gain medium to couple with a micro-disk (MD) resonator. By adjusting the diameter of the MD, the resonant wavelength of the trion laser can be matched. Trion emission demonstrates superior gain characteristics, suggesting that trion lasers might have a lower threshold, making them suitable for applications in monolayer TMDCs lasers.

  Preview abstract

Active single-mode crystalline fiber can improve the laser performance of its bulk form regarding heat dissipation and pump/signal mode matching. The ultra-broadband emission from Ti:sapphire crystal has advantages compared to semiconductor optical amplifier based tunable lasers for high axial-resolution optical coherence tomography. The study achieved a 99% optical energy transmission through a single-crystalline core and clad Ti:sapphire fiber. The crystalline clad was produced using solid-state growth at 1650 °C for 60 hours. The crystallographic orientation distribution and fluorescence mapping at the fiber end-face were characterized.

  Preview abstract

We investigate the hybrid integration of two photonic crystal nanobeam resonator
designs with a Si waveguide, including a nanocavity and a band-edge resonator. Both
integrations demonstrate remarkably high unidirectional coupling efficiencies, exceeding 80%.
In experiments, we have successfully achieved these hybrid integrations using the highly
precise transfer printing method relying on mechanical guidance.

  Preview abstract

We present the ultra-thin flexible Ag-NPs/PMMA SERS substrates for the real-time, in-situ antibiotic detection on the fish surface. The used Ag NPs are photoreduced on the nanotip-equipped ferroelectric template and then transferred to a PMMA film. The nanotips on the template surface can produce strong electrostatic field through the lightning rod effect to enhance the photoreduction rate and increase the transfer efficiency. The superior SERS performance includes high sensitivity, the enhancement factor up to 1010, the limit of detection of 2.38×10^-12 M for standard detection and 2.08×10^-10 M for practical detection on irregular fish surface.

  Preview abstract

All inorganic perovskite (CsPbBr3) quantum dots are utilized as artificial synaptic devices for biomimetic visual neural systems, effectively integrating optical sensing and electrical memory functionalities. This enables a direct modulation in external optical stimulations, thereby facilitating real-time conversion and transmission in optoelectronic signals. Furthermore, it is feasible to emulate the characteristics of synaptic plasticity by simply applying electrical signals to activate the resistive random-access memory (RRAM) devices.


  Preview abstract

In this study, we present a novel approach to enhance the water resistance of CsPbBr3 perovskite quantum dots (PQDs) by encapsulating them within metal-organic frameworks (MOFs). The hierarchical structure consists of a gold thin film on top, CsPbBr3 PQDs embedded within MOFs in the middle layer, and a TiO2/SiO2 distributed Bragg reflector (DBR) on the bottom. Our investigation reveals the presence of strong light-matter coupling and Rabi splitting phenomena within this composite structure. This innovative design offers promising opportunities for developing advanced photonic devices with improved stability and optical properties, opening up new avenues for optoelectronic applications..

  Preview abstract

As Si3N4-based photonic integrated circuits emerge as a promising platform, it is important to diagnose their spatial configuration with resolution beyond diffraction limit. Here, we demonstrate a resolution enhancement of hundred-nanometer-diameter Si3N4 nanowires based on photothermal nonlinearity. Our work opens up the avenue for super-resolution imaging of Si3N4 NW by photothermal nonlinearity and SAX subtraction method, which has the potential to exceed the diffraction limit through higher order SAX subtraction.

  Preview abstract

The efficient single-photon up-conversion photoluminescence (UCPL) feature was found in 2D lead halide perovskites, and it promises for developing laser cooling devices. In this study, we report the discovery of single-photon up-conversion photoluminescence (UCPL) in 2D lead halide perovskites. The observed UCPL phenomenon involves anti-Stokes photoluminescence (ASPL) and is also referred to as phonon-assisted up-conversion or thermal up-conversion, ASPL removes thermal energy from the system, in turn cooling it. This finding opens up new possibilities for harnessing the unique properties in optoelectronics and photonics applications.

  Preview abstract

Photon avalanche (PA) upconversion luminescence (UCL) of rare earth ion-doped upconversion nanoparticles (UCNPs) have attracted great interest due to their extreme nonlinear response to the excitation light intensity via a looping energy transfer mechanism. In this work, we demonstrated the generation of PA UCL of Tm3+-doped NaYF4 UCNPs with an excitation intensity threshold of 6 kWcm-2. Furthermore, we showed that the excitation intensity threshold of the PA UCL of these core UCNPs can be reduced by the guided mode resonance effect generated by a resonant waveguide grating structure.

  Preview abstract

Room-temperature phosphorescence (RTP) two-dimensional (2D) organic inorganic hybrid perovskites (OIHPs) that possess efficient triplet energy transfer between inorganic parts and organic cations have been seen as promising materials in optoelectronic devices. However, the development of RTP 2D OIHP-based photomemory has not been explored yet. In this work, the spatially addressable RTP 2D OIHPs based non-volatile flash photomemory is first investigated to explore the function of triplet excitons in elevating the performance of photomemory. Thanks to the triplet excitons generated in RTP 2D OIHP, extremely low photo-programming time of 0.7 ms and multilevel behavior of minimum 7 bits can be achieved.

  Preview abstract

We demonstrate a MoS2/Si heterojunction device stacked by utilizing a polymer-assisted all-transfer-printing method. The monolayer MoS2 film is transferred onto the patterned SiO2/p+-Si substrate assisted with PDMS template pad to form a heterojunction. Then, the patterned Pt/Au electrodes defined by photolithography and deposited on the glass substrate are transferred onto MoS2 assisted with water-soluble polyvinyl alcohol (PVA) to form a photodiode. Compared to the sample fabricated by the traditional photolithography process, this proposed method can avoid photoresist residue and organic solvent, and the photoresponsivity increases ~30 times.

  Preview abstract

The integration of metasurface and light source has received tremendous attention. However, to obtain efficient beam deflection, some previous studies lack efficiency at large deflection angle, thus limiting the coverage of deflection angle. Here we numerically demonstrate high-efficiency Si-based homo-metagrating that unitize Si substrate to reduce impedance mismatching with InP-based 1550-nm photonic crystal surface emitting laser (PCSEL). We manipulate two degrees of freedom: overall add-on phase and parameters of meta-atoms in a period to optimize the efficiency. We believe the low cost of silicon and the maturity of its fabrication has great advantages for integration within numerous ultracompact optical systems.

  Preview abstract

Herein, for the first time, we report efficient N–I–P architecture PeLEDs using solution-processed polyethyleneimine ethoxylated-doped SnO2 (SnO2:PEIE)as an electron transport layer. According to the results, perovskite layer deposited on PEIE-doped SnO2 can achieve better electrical characteristics and crystallinity than pristine SnO2. As a result, PeLEDs based on SnO2:PEIE can achieve a low driving voltage of 1.2 V and an external quantum efficiency of more than 14%.

  Preview abstract

Addressing fidelity challenges in photolithographic metalenses is essential for advancing dielectric metalenses adoption in optoelectronic applications. This study presents an innovative reticle modification system guided by a predictive neural-network U-net lithographic model. This correction enables precise control of photoresist dimensions, with a remarkable average deviation of only 0.19% from the target. Additionally, we achieve vertical etch profiles with a high 1:5 aspect ratio across an 8-inch wafer. Consequently, we showcase visible metalenses (2mm diameter) achieving diffraction-limited focusing using DUV KrF 248 nm photolithography. This research bridges semiconductor processes and lens manufacturing, enabling high-volume production of versatile metalenses and metasurface applications.

  Preview abstract

We elucidate general scattering relationship between one-dimensional parity-time symmetric unit cells and its resultant photonic crystals. As arbitrary unit cells operated at an exceptional point and broken symmetry phase would always lead to form bands, while ones operated at some symmetry phases with specific transmission phase would construct bandgaps. With an increase of non-Hermiticity, the edges of bands would gradually move toward the center of Brillouin zones.
Any finite periodic systems made of unit cells having exceptional points or broken symmetry would eventually exhibit transmittance of T>1, consistent with an extension of generalized conservation relation proposed by Ref.[1].

  Preview abstract

The rise of van der Waals (VDW) materials, especially MoS2 and antimonene, has significant implications for semiconductor technology. MoS2 shows promise as a high-performance semiconductor due to its good electric properties. Antimonene, with much reduced contact resistance when grown on top of MoS2 as compared to traditional metal materials, is a notable approach for future electrode. This work reports the observation of low effective elastic constant of VDW interaction between antimonene and MoS2, to be on the order of 2 × 10^18 N/m^3. This work will trigger future studies of VDW interaction on the contact resistance.

  Preview abstract

This study presents a novel approach involving the fabrication of gold (Au) nanohole arrays (ANA) decorated with ring-shaped silver nanoparticles (AgNPs) on a silicon dioxide (SiO2)/silver (Ag) substrate. The surface plasmon resonance coupling in terms of the photoluminescence (PL) reactions of ANA substrates with and without ring-shaped AgNPs is investigated via experiments and numerical simulations. Specifically, the Raman signal of rhodamine 6G (R6G) dye and the PL intensity of DCJTB molecules are significantly enhanced 3.7 and 2.2 times, respectively, compared to those of the bare ANA substrate. Meanwhile, the PL lifetime is reduced by 46.15%.

  Preview abstract

In this experiment, we employ the photoalignment material Brilliant Yellow (BY) as the horizontal alignment layer and Polyimide (PI) as the vertical alignment layer in the liquid crystal cell. By exposing BY to polarized ultraviolet light, we can modify the alignment direction of the horizontal layer, consequently altering the arrangement of the liquid crystals. As a result, the liquid crystal molecules on both sides of the Liquid Crystal Networks (LCNs) film exhibit distinct orientations. This alignment can control the bending behavior of the LCN film.

  Preview abstract

We successfully synthesize red perovskite quantum dots (QDs) with the CIE color coordinate at (0.7034, 0.2852), which is closely resembling the standard red color (0.708, 0.292) that is specified by Rec.2020. These QDs are mixed with polyvinyl cinnamate (PVCN) to formulate photopatternable thin films. Therefore, we can pattern the films with conventional photolithography techniques. The minimum feature sizes that we achieved is as small as 3.30 μm. The combination of red perovskite QDs with PVCN shows great potential for serving as effective color conversion layers for micro-LEDs in the future.

  Preview abstract

In this work, we utilized a novel material called HT-CTP as the sensing material
for a nanoscale vertical pore structure organic semiconductor gas sensor. The experiments
were conducted under controlled conditions with humidity maintained below 15% and an
operating voltage of 5 volts. The results of the experiments revealed that the new material,
when used in the nanoscale vertical pore structure organic semiconductor gas sensor, exhibited
excellent performance in detecting low concentrations of nitrogen oxides with a detection limit
lower than 100 ppb.

  Preview abstract

Here, we report a new strategy to sputter ZnGa2O4 thin films (ZGO) on β-Ga2O3 thin films (GaO) and annealed at different temperatures in air to enhance the quality. In this work, the ZGO/GaO structure performances a low dark current and high sensitivity as a UV photodetector. After annealed at 1000 °C in air for 30 mins, the photocurrent of ZGO/GaO significantly increased from 2.85×10-7 to 2.95×10 -4 due to the quality of materials is greatly improved. In addition, ZGO/GaO annealed at 900 °C performances the best sensitivity which as high as 6.42×10 3 .

  Preview abstract

This work uses UVC to induce poly-thymine ssDNA dimerization and develops two surface-enhanced Raman scattering methods for validation. One employs self-assembled SERS substrates to measure dry DNA samples, and the other uses gold nanoparticles whose citrate caps have been removed, to sandwich the DNA strands in aqueous solutions. A crucial element in our lab's strong coupling system involves fluorescent molecules embedded in ssDNA. By altering ssDNA conformation with dimerization, it is possible to finely tune the dipole moment orientation of fluorescent molecules, which can enhance its coupling strength to a nanocavity.

  Preview abstract

Three conjugated polyelectrolytes (CPEs) PFN-Br, PFN-BF4, and PFN-PF6 were utilized solely for surface modification of zinc oxide nanocrystals (ZnO NCs). ZnO films were smoothened by CPEs that allowed flat deposition of the perovskite absorbing layers. The improved contact between ZnO and perovskite layers was beneficial for reducing leakage current, and the incorporation of CPEs passivated the defects of ZnO films to prolong carrier lifetime of upper CsPbBr3 NCs. The device based on PFN-Br showed the highest device performance, while the one based on PFN-BF4 exhibited better current efficiency over PFN-Br under the low current density below 160 mA/cm2.

  Preview abstract

The low filling factor of LCs in the LC-polymer composite systems greatly affects the electro-optic properties of optically isotropic liquid crystal devices. To overcome this issue, we proposed an encapsulated LC which is fabricated through oil-in-water encapsulation, effectively increasing the filling factor by closely packing the capsules. This led to a thin-composite film of nano-size LC encapsulation that reliably switches from isotropic state to anisotropic state in response to a low-voltage electric field, with fast response time and no hysteresis. The improved electro-optic performance of the encapsulated LC device has broad applications in flexible display and tunable photonic systems.

  Preview abstract

In this study, we presented the design of active metasurfaces via coherent all-optical control. Two counter-propagating light beams were used to tune the phase gradient of the metasurface, which in term realizes a wide beam steering angle up to 38 degrees. Our scheme provides a versatile strategy toward the realization of high-performance active metasurfaces for beam steering applications.

  Preview abstract

Spectral analysis has found extensive use across various applications. Nevertheless, conventional benchtop spectrometers are both bulky and costly. As a result, the miniaturization of spectrometers has emerged as a trend. This work employed UV nanoimprint lithography to pattern a metasurface on a high refractive index TiO2 dielectric material. The optimization of the UV nanoimprint lithography and ICP etching process were key aspects of the fabrication. The spectral responses of the fabricated metasurface units were measured. The metasurface is intended to undergo testing as an on-chip spectrometer, offering a more compact and cost-effective solution.

  Preview abstract

We present a novel structure, CsPbBr3 QDs/1T’-MoTe2 MvdWHs, achieved through wafer-scale integration, which exhibits exceptional photogating properties. Under illumination, this structure enhances output photocurrent by 4100% at gate voltage = -7V. Incident photons are absorbed within the QDs, generating photogenerated carriers and creating a photogating effect in the 1T’-MoTe2 layer. The work function mismatch induces an internal electric field at the interface, rapidly bending energy bands, facilitating photogenerated hole transfer to 1T’-MoTe2 under negative back gate voltage, resulting in an overall increase in device photocurrent.

  Preview abstract

We presented the analysis of photonic band gap in disordered tetrahedral networks. We showed that the band edges of the gap can be explicitly manipulated by introducing specific types of structural perturbation. The analysis may further provide design and manipulation strategies of engineered photonic band gap based on disordered media.

  Preview abstract

Ultrafast lasers with short pulse duration have shown a variety of applications. Carbon nanotubes have shown promising results as saturable absorbers in ultrafast devices, and in the last decade the methods of fabrication and implementation have been vastly improved. In this research we report the fabrication and characterization of a passive modulator using single walled carbon nanotubes in sodium carboxymethyl cellulose as a host polymer. With these results we can confirm if the fabricated modulator can be used as a passive mode locker as a low-cost alternative for a fiber laser at University of Costa Rica.

  Preview abstract

In this study, black phosphorus quantum dots (BPQDs) are prepared by the liquid phase exfoliation method, and then introduced to the TiO2 photoanode of the dye-sensitized solar cells (DSSCs). The influence of BPQDs prepared with different ultrasonic vibration times on the photovoltaic conversion efficiency of DSSC is investigated. It is found that the efficiency increases with the vibration time. Moreover, the maximum efficiency is obtained with the vibration time of 15 hours. Compared with the pure TiO2 photoanode, the efficiency of DSSC increases from 4.77% to 5.68% when BPQDs is introduced to the photoanode.

  Preview abstract

The pair number of quantum well (QW) and composition of InGaN for InGaN-based multiple QW (MQW) solar cells are investigated and optimized numerically using APSYS. Analysis shows that excessive increase in QW pair number causes worse FF, and excessive increase in indium composition results in the increase of piezoelectric field in QWs, which hinders light-generated carriers from transport. Both result in a decrease in conversion efficiency. This study shows that In0.21GaN MQWs with 18 pairs exhibits the optimal conversion efficiency. A final 31.7% improvement is achieved in this study.

  Preview abstract

An external magnetic field enhances the typical photocatalysis mediated by the Au-TiO2 composite nanoparticles in the photocatalytic degradation of methyl orange in water. The applied magnetic field further strengthens the plasmonic enhancements induced by additional visible light illumination of various colors of blue, green, and red, while all processed with UV light.

  Preview abstract

Over the past decade, our research has been dedicated to in-depth investigations of scarab beetle cuticle properties through Mueller matrix spectroscopic ellipsometry. This explorationhas not only unveiled the intricate optical characteristics of these natural materials but has also sparked the development of novel synthetic materials. In this presentation, we will showcase the potential of this research through the utilization of cellulose nano-fibrils for camouflage applications, as well as cellulose nanocrystals (CNCs) and AlN-based thin films to generate circularly polarized light. We will
discuss our latest findings, demonstrating the capabilities of CNCs as optical diodes for circularly
polarized light and non-reciprocal reflection properties of magnetron sputtered HfAlN thin films.

  Preview abstract

Janus metasurfaces provide degree of freedom by imparting the light with the different incident direction. Directional Janus metasurfaces operating at microwave and near infrared region have been demonstrated several years ago. However, the multilayer design of the Janus metasurface is an addition of difficulty for fabrication. Here, we experimentally demonstrate monolayer Janus metasurfaces in the visible with TiO2 nanopillars. By taking advantage of the propagation and geometric phase control, different desired states of orbital angular momentum (OAM) for two opposite directions are achieved. We believe the direction-dependent metasurface has the potential in holograms, laser mode modulation and optical combiner.

  Preview abstract

We present a novel depth sensing system for facial recognition applying metasurfaces and photonic crystal surface-emitting lasers (PCSELs). Our lens-free, single-shot system projects 45,700 infrared dots from a compact 297² μm² sample area, offering a wide 158° field-of-view (FOV) with low power consumption. Compared to traditional dot projectors, our design is 233 times smaller and consumes 5-10 times less power due to PCSELs. The GaAs-based meta-hologram and simple optical architecture make it lighter and more energy-efficient, suitable for wearable devices. This technology overcomes limitations of bulky dot projectors, paving the way for integration into compact wearable devices.

  Preview abstract

This research aims to address the challenge of the lack of geometric and material data
in the study of photonic metasurfaces. We employed a conditional deep convolutional
generative adversarial network to train the model, and through continuous parameter
optimization, we achieved the capability to predict geometric structures and material
information solely based on spectral data. Subsequently, we used the rigorous coupled-wave
analysis simulation method to observe the consistency between the simulated spectra and the
target spectra.

  Preview abstract

Metalenses ,which are thinner than conventional lenses ,usually fabricated using electron beam lithography. However, this method is costly and not suitable for rapid mass production. Therefore, nanoimprint lithography has become an ideal solution to this problem. In this work, we are going to fabricate a metalens with a size of 330µm*330µm by nanoimprinting. First, we transfer the pattern of the metalens onto the polymer Topas8007 as a stamp for the nanoimprint. The pattern on the Topas8007 stamp is a reversed structure. Subsequently, the pattern is transferred onto the photoresist material using the Topas8007 stamp.

  Preview abstract

We design and fabricate an emitter on the silicon photonic platform to generate a 2D Gaussian beam into free space. We first engineer the coupling from a strip waveguide to a slab waveguide for mode expansion in the first dimension. The light in the slab waveguide then gradually out-couples to free space via a meta-grating and achieves mode expansion in the second dimension. We experimentally demonstrate a mode conversion from a 450 nm × 220 nm waveguide to a 2D free-space Gaussian beam with a 1/e2 beam diameter of 58.4 µm.

  Preview abstract

We demonstrated a D1 defect photonic crystal defect laser with structural variations, and compared the lasing properties with the unperturbed D1 photonic crystal defect cavity. The high circular polarization lasing action was observed from the photonic crystal defect cavity.

  Preview abstract

We demonstrate a chip-scale confocal microscope based on a 30-element active optical phased array (OPA). We calibrate the fabrication-induced phase errors with a novel algorithm, showing 10 times faster convergence than the genetic algorithm. We perform confocal depth sensing by dynamic scanning of the focal length. Using the OPA-based microscope, we reconstruct a 3D topology image that resolves a height difference of 8.05µm.

  Preview abstract

We experimentally demonstrated an unprecedented simple way to excite strong and broadband toroidal dipole (TD) response in the optical regime using dielectric metasurfaces upon plane-wave excitation. The peculiar electromagnetic portrait of TD metamaterials leads to an ultrahigh sensitivity for local refractive-index sensing. In addition, the effect of the coupling between TD and magnetic dipole (MD) moments on the nonlinear third-harmonic generation (THG) was investigated. A strong THG enhancement was found at the generalized Kerker effect, referring to the constructive interference between the total electric dipole (the sum of electric dipole and TD moments) and the MD mode. In order to further narrow down the resonant linewidth, several asymmetric structures such as tilted nanorod pairs and asymmetry kite-shaped nanopillars were designed to excite high quality factor resonances based on the concept of quasi-bound state in the continuum (quasi-BIC) and applied to sensing and nonlinear signal conversion.

  Preview abstract

The quasi-Bound States in the Continuum (quasi-BIC) is a resonance characterized by ultrahigh quality factor (Q-factor) with strong near-field distributions. We designed periodic amorphous silicon kite-shaped nanopillar arrays to achieve Fano-lineshaped quasi-BIC resonance supported by magnetic dipole (MD) and electric quadruple (EQ). Varying the asymmetry parameters of the kite-shaped structure leads to dramatic Q-factor variations and strong field confinement, which is beneficial for boosting nonlinear effects for third-harmonic generation (THG). The simulated (experimental) TH signal reaches more than four orders (one order) of magnitude enhancement at the quasi-BIC resonant frequency. This approach offers a platform for realizing tunable nonlinear metasurfaces.

  Preview abstract

Two-dimensional perovskites have become the trending materials for various photoelectric applications because of their excellent optoelectronic performance. However, the formation of self-trapped exciton attributed to the strong exciton-phonon (E-P) interaction in 2D perovskites, affects the optoelectronic performance significantly. Here, various optical spectroscopy analyses study the influence of E-P interaction on carrier dynamics for phenethylammonium lead bromide (PEA2PbBr4). Results suggest the strength of E-P interaction is relative to the residual strain of thin films. Moreover, the numerical fitting result of time-resolved photoluminescence (TRPL) shows the reduction in E-P interactions further enhances the recombination process of free excitons.

  Preview abstract

We demonstrated GeSn micro-disk monolithically-integrated on silicon substrate. The introduction of sufficient Sn (~10%) into the GeSn active layer successfully transfer the material into a direct-bandgap material. High-Q micro-disk cavity was fabricated. Under optical pumping, lasing action was achieved with a lasing wavelength of 2201 nm up to 120 K. These developed GeSn micro-disk lasers provide a practical solution for compact light sources for silicon photonics.

  Preview abstract

This study presents finding on the exceptional plasmonic characteristics of 2D Ti3C2Tx MXenes in the short-wave infrared (SWIR) range. We report the discovery of a strong plasmonic effect through acoustic plasmon modes, resulting in a significant reduction of the operating wavelength in the SWIR region that exceeds the performance of conventional 2D materials. Utilizing this breakthrough, we achieved an unprecedented nonlinear absorption coefficient of 1.37 × 10^(-2) m/W at a 1.56 μm wavelength. These unique optical properties are attributed to MXene's high electron density and distinctive two-dimensional structure.

  Preview abstract

Metasurfaces, comprised of subwavelength structures which provide the capability
for arbitrary phase manipulation of electromagnetic waves, have been developed for decades to
replace conventional and bulky optical components. Recent development of “J-plates” achieve
distinct orbital angular momentum (OAM) states for two arbitrary orthogonally polarized
incident beams. However, the operating wavelength of most J-plates are in the visible. Here, we
experimentally demonstrate a J-plate operating at 940 nm that generates the high-quality vortex
beams with different OAM states. This device has the potential applications in various optical
fields, including near-infrared optical communication and stimulated emission depletion (STED)
microscopic imaging.

  Preview abstract

We design and fabricate grating emitters with unidirectionality and high angular dispersion. We break the symmetry between top and bottom emitting directions by choosing SU-8 as the top cladding. The refractive index contrast between the top cladding (SU-8) and the bottom cladding (SiO2) allows the phase-matching condition to be satisfied only for upward diffraction. The design is verified with finite-difference time-domain (FDTD) simulation. We measure unidirectionality of 83% and angular dispersion of 0.809°/nm from the fabricated device.

  Preview abstract

This research introduces a novel approach for mass production of high refractive index TiO_2 composite UV-resin for terahertz (THz) regime tailored for Masked Stereolithography (MSLA) 3D printing enabling versatile design of compact THz passive devices. Its careful formulation process balances a heightened refractive index (n=1.9) in THz regime while retaining low absorption coefficient, yielding impressive performance and compactness in a THz plano-convex lenses and other THz passive devices. This advancement holds vast potential for diverse, cost-effective applications in compact THz telecommunication and imaging systems, presenting an exciting leap forward in 3D printing technology.

  Preview abstract

By substituting the heavy Cs element at the A sites of perovskite quantum dots (QDs), highly luminescent FA1-xCsxPbBr3 QDs is synthesized using a room temperature ligand-assisted re-precipitation method. The QD powder is blended with polydimethylsiloxane (PDMS) and employed as a scintillator, resulting in increased photoluminescence (PL) under X-ray illumination (radioluminescence). Utilizing PDMS for the fabrication of QD films provides effective protection from moisture and oxygen. High-quality X-ray images are obtained using these scintillators prepared with perovskite QDs.

  Preview abstract

High-power multiple cascaded lasers based partially-corrugated-grating (PCG) DFB structures are advanced to overcome the challenging issues of on-board light sources for co-packaged optics (CPO) applications. With the systematic design of multi-section PCG-DFBs, the device could preserve a single-wavelength operation, high side-mode suppression ratio (SMSR), and low relative intensity noise (RIN). This provides the high-reliability and high-efficiency in implementing cascaded DFB lasers to improve the performance and enhance the output power. By designing a grating ratio of 0.4 and five segmentations, the laser can provide >13.8% improvement in output power, >231 mW output, <-151.75 dB/Hz RIN, and >0.4395 mW/mA slope efficiency.

  Preview abstract

There is a common belief that the inherent dispersive phase-matching nature and the imperfect collimation of the typically used thermal sources restrain the performance of the photonic crystal guided resonance (PCGR) in mid-infrared, the spectral domain of fundamental importance to vibrational molecular spectroscopy [Wu et al., Nat Commun 2014, 5, 3892]. Here, we question this belief and numerically demonstrate a high angular tolerance of the dielectric PCGR in mid-infrared by judiciously engineering its dispersion.

  Preview abstract

In this work, various morphologies of CsPbBr3 quantum dots were prepared using the hot-injection method. The successful realization of single-layer quantum dot light-emitting diodes (LEDs) was achieved. Furthermore, different morphologies of quantum dots were stacked in heterojunctions, and effectively and easily enhancing carrier injection.

  Preview abstract

The study examines thermal modification and the z-scan technique for measuring optical nonlinearity. Thermal modification involves heat-induced property changes, widely used in fields like materials science. z-scan analyzes light intensity on a focal plane to study material behavior. Glass's nonlinear absorption was measured using z-scan, yielding absorption coefficient β. This β aided simulating glass modification by temperature estimation. Results showed nonlinear absorption governing material heating. Simulations confirmed laser pulse's effectiveness in modifying glass across its thickness.

  Preview abstract

Utilizing the Pancharatnam-Berry (PB) phase as means of phase modulation in metasurfaces is an effective strategy. However, signals subjected to PB phase modulation commonly manifest symmetric characteristics within circular polarization (CP), which can diminish the signal-to-noise ratio for specific CP states. In this study, an all-dielectric chiral metasurface is harnessed in conjunction with principles of topological photonics to disrupt the CP symmetry in metasurfaces, thereby enhancing the signal-to-noise ratio in far-field.

  Preview abstract

Recently, there has been a significant surge in research on two-dimensional transition metal dichalcogenide (TMDC) semiconductor lasers. Our approach involves a specialized method wherein we integrate a metal ring atop WSe2 and pair it with a silicon nitride microdisk resonator. This unique combination gives rise to a hybrid mode that merges the whispering-gallery-mode (WGM) with the surface plasmon mode. As a result, it leads to an enhanced overlap with the monolayer WSe2 and ensures a favorable quality factor. It is expected that this work will contribute to significant breakthroughs in optical communication and quantum technology fields.

  Preview abstract

An ion-gel film consisting of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]) and poly(vinylidene fluoride) (PVDF) was used as a dielectric layer to fabricate poly-[2,5-bis(3-tetradecyl-thiophen-2-yl)thieno[3,2-b]thiophene] (PBTTT)-based TFTs. The ferroelectricity of the ion-gel film is enhanced by the addition of [EMIM][TFSI] into PVDF. The devices can operate at ultralow voltage as a result of the formation of electric double layer. With the ion migration and ferroelectric properties of the ion-gel film, the devices are able to perform a variety of synaptic behavior.

  Preview abstract

1-T phase Vanadium Disulfides (VS2) has metallic property[1], compare to its semiconductive 2-H phase. We synthesized VS2 with VLS method and salt-assisted precursors through APCVD[2]. Then we confirmed our VS2 belongs to 1-T phase semimetal material through TEM and temperature-dependent I-V measurement. We transferred VS2 on WS2 to build VS2/WS2 heterostructure. We identified VS2 and WS2 in heterostructure with Raman measurement and OM image. From now on, we experimented semimetal bismuth perform as contact material. Compare to chromium, bismuth contact shows ohmic contact and lower contact resistance. In future, VS2/WS2 heterostructure would experiment to compare with bismuth contacts.

  Preview abstract

A comprehensive understanding of fluorescence properties in cellulose films is required to advance cellulosic fluorescence films. We acquired the fluorescence properties including the quantum yields, lifetimes, and rates of the radiative k_r and nonradiative k_nr decay of fluorescein isothiocyanate (FITC) and FITC-labeled cellulose (FLC) in methanol, ethanol, and aqueous solutions as well as FLC films. The fluorescence quantum yields of FLC are found to be very low compared to those of other samples, which may be more significantly caused by anomalously reduced k_r of FLC than increased k_nr.

  Preview abstract

We present ethanol-assisted photoreduction synthesis of silver nanoparticles (Ag NPs) on the UVC illuminated ferroelectric templates for the SERS application. The ethanol-assisted photoreduction not only increases the density of silver seeds but also enhance the growth rate of Ag NPs. A large amount of Ag NPs produce high-density hotspots, which can effectively enhance the Raman signal intensity of analytes by electromagnetic mechanism. Compared with the sample prepared without ethanol assistance, the Raman signal intensity can be enhanced by 4.87 times. The prepared SERS substrate has an ultra-low limit of detection 1.47×10^-9 M and a high enhancement factor of 2.34×10^9.

  Preview abstract

This research discusses Schottky mid-infrared (MIR) photodetector (PD), where the probability of hot carrier crossing Schottky barrier is enhanced by adjusting hot carrier diffusion distance. A mathematical model is employed to validate experimental results of hot carrier diffusing to and leaping over the barrier, thereby improving the responsivity of the device. As a result, for Ag thin film thickness of 20 nm, the response at 3.46 μm wavelength is 6.46 times higher than the device with 10 nm thickness.

  Preview abstract

In this study, nonahydrated aluminum nitrate was used as the source of aluminum.
The aluminum was mixed with zinc oxide and then grown using a hydrothermal method to form
zinc oxide nanorods as the electron transport layer. The performance of the perovskite solar
cells based on non-doped and 1% Aluminum-doped zinc oxide nanorods was compared, and it
was found that the device with aluminum doping exhibited the higher efficiency.

  Preview abstract

A plasmon thin film transistor of Al2O3/ZnO/HfO2 channel is deposited on ITO substrate by atomic layer deposition. Au nanostructures are formed on the channel surface by as-deposited 3nm gold thin film. The as-deposited Au nanostructures in air (n =1) absorb incident light of = 680nm, and the photo-generated hot carriers are amplified by the TFT to reach a high responsivity of R = 2.1 A/W. When the Au nanostructures coated by refractive index oil n = 1.64, the responsivity peak R = 1.2 A/W is red-shifted to near-infrared  = 730nm.

  Preview abstract

The PEDOT/WO3/ZnO porous film were prepared with electrochemical polymerization, sputtering, and hydrothermal method for energy-saving window applications. The electrochromic analysis showed that the composite film exhibited a contrast ratio of 42.8% at wavelength 650 nm, with high ion diffusion coefficient and rapid response during coloring (2.8 s) and bleaching (1.3 s). After 50 redox cycles, the current density of the composite film decreased by 18.8%. However, a stable response was observed when the number of cycles was further increased. The coloration efficiency of the PEDOT/WO3/ZnO was 54.48 cm2/C, which was better than the film prepared with a WO3/PEDOT/ZnO structure.

  Preview abstract

Besides the crystallinity of the grown MoS2, high contact resistance at electrode/ MoS2 interface and the inferior influence from the dielectric layer are also possible mechanisms responsible for the inferior performances of MoS2 transistors. Through the improvement of the crystallinity of the au electrodes, sequential film transferring instead of direct bi-layer MoS2 growth and the isolation of the MoS2 channel from the SiO2 dielectric layer, the MoS2 transistor with enhanced field-effect mobility values from 0.27 to 1.33 cm2V-1∙s-1 is observed. High ON/OFF ratio 100000 is also observed. The possibility of scalability is advantageous for the practical applications of 2D materials.

  Preview abstract

In this work, we analyze the Si-based germanium IR photodetector that we have fabricated. Due to the difference in lattice constants between germanium and silicon, there is great difficulty in high-quality germanium epitaxial. Therefore, we fabricated a thin-film PIN photodiode with a rocky top silicon layer. We analyzed the device and thin-film deposition with scanning electron microscopy (SEM). The quality of the deposited material was analyzed by Raman analysis, and the optical properties were measured and analyzed.

  Preview abstract

This study introduces a novel method of passivating perovskite quantum dots (PQDs) using Al2O3 and atomic layer deposition (ALD). This technique shields PQDs from moisture, oxidation, and temperature changes, maintaining their stability and reliability. It exhibits robust performance in various tests including long-term lighting aging and temperature/humidity conditions (60°/90%). By integrating with micro-LED and red phosphor, we fabricated a white light system with a data transmission rate of 1 Gbit/s. This approach opens promising avenues for full-color micro-displays and high-speed visible light communication (VLC) applications, offering a significant advancement in PeQDs passivation.

  Preview abstract

In this study, we demonstrate the fabrication of microring resonators using nanoimprint technology. Silicon nitride (SiN) resonators with high quality (Q) factors up to the order of 105 can be realized by nanoimprinting lithography (NIL). In addition, by properly
designing the waveguide geometry, nearly-zero waveguide dispersion can be achieved. This work offers the promising potential to fabricate microring resonators in a significantly costeffective and process-friendly scheme.

  Preview abstract

In recent years, with the rise of artificial neural networks, researchers have developed devices using halide perovskites for artificial synapses. Lead halide perovskites have shown successful applications, but their toxicity limits future development. To address this, we used eco-friendly Cs3Bi2I9-xBrx as the active layer, achieving superior performance in Cs3Bi2I6Br3 (x = 3) with improved crystallinity, reduced dark current, and optimal synaptic behavior. It shows promise for efficient artificial synaptic applications.

  Preview abstract

In the present work, we theoretically study the optical multistability in a hybrid system consisting of an optomechanical cavity with quantum dot molecules inside it coupled to an auxiliary cavity via a single-mode waveguide. We obtain the expression for the primary cavity photon number by solving the Heisenberg-Langevin equations of motion in the steady state limit, which indicates the presence of optical multistability phenomena in the proposed system. We show that various system parameters can control and modulate the optical multistability curves, which can be utilized for designing and optimizing sensitive all-optical switching devices at low power and optical sensors.

  Preview abstract

We experimentally demonstrate the first period-chirped silicon blazed gratings by laser interference lithography and wet chemical etching. The resultant gratings have a period change over 110 nm that enables more than 200 nm of wavelength coverage when it serves as the dispersive element to resolve the incident light spectrum.

  Preview abstract

In this study, we utilized molecular beam epitaxy to grow the Type-II superlattice (T2SL) structure. By adjusting the Arsenic flux during the growth of the InAs layer, we investigated the influence of the V/III ratio on photoluminescence and x-ray diffraction of SWIR T2SL. X-ray diffraction patterns indicated an enhanced strain control down to 0.07%. The low-temperature photoluminescence analysis revealed that the sample with a lower V/III Ratio exhibited higher luminescence intensity. The findings from both measurements underscore the importance of adjusting the V/III Ratio for the InAs layer during the growth of the T2SL structure.

  Preview abstract

This study explores the extension of quantum dot (QD) wavelength to approximately 1.38 μm on GaAs substrates. Utilizing molecular beam epitaxy (MBE), we investigate the impact of InGaAs strained buffer layer (SBL) thickness on InAs Quantum Dots (QDs). Photoluminescence (PL) spectra reveal a redshift and narrower FWHM value as SBL thickness increases. Atomic force microscopy (AFM) analysis demonstrates a clear trend between SBL thickness and quantum dot density. Optimal SBL thickness enhances uniformity and density, promising applications in facial recognition, automotive lidar, and optical communication.

  Preview abstract

Metamaterial-based nanophotonic devices were numerically analyzed using the FDTD method to study polarization converters with high transmission and wide bandwidth in the optical and terahertz frequency ranges. First, the transmission characteristics of the incident polarization angle of the proposed polarization converter in the optical frequency band were investigated, and it was found that the transmitted light becomes clockwise circularly polarized when the incident linearly polarized light is 45°. Furthermore, similar results were obtained in the terahertz band, and a high-performance polarization converter was realized.

  Preview abstract

InGaN-based Green vertical cavity surface emitting laser structure had been demonstrated with top dielectric reflector and bottom porous distributed Bragg reflector (DBR). The electroluminescence (EL) spectra of the InGaN device without and with top dielectric mirrors were analyzed. The central wavelength and stopband width of porous DBR structure were measured at 522nm/75nm with 66.3 nm-thick porous GaN and 58.7 nm-thick non-etched GaN layer of the 20-pair stack structure. For the VCSEL structure, the line width of the ST-LED structure was reduced from 34.5 nm at 509.7 nm and 2.18 nm at 520.8 nm for the VCSEL structure.

  Preview abstract

The photo-electrical and synaptic properties of flavin-doped DNA biopolymer devices are presented. The wavelength-dependent electric characteristics and the implementation in neuromorphic computing are demonstrated, which may facilitate the development of biomaterial-based devices with neuromorphic functionalities.

  Preview abstract

The plasmonic resonance characteristics of heavily Ga-doped ZnO (GaZnO) epilayers grown with sapphire substrate temperatures 235, 250, and 265 oC corresponding to Ga doping concentration 4.6, 3.5, and 3.0 at.% of molecular beam epitaxy (MBE) are explored. Hall effect measurements of epilayers show that free electron concentration reaches around 1021 cm−3. The plasmonic resonance wavelength are 1377, 1385, 1436 nm for Ga doping concentration 4.6, 3.5, and 3.0 at.%, respectively. Lower strain, loss, and surface roughness are observed in sample with doping concentration 3.5 at.%. All samples demonstrate columnar structures of GaZnO epilayers in scanning transmission electron microscope (STEM) images.

  Preview abstract

We propose a way to take advantage of the mechanical properties of a twodimensional graphene layer to unlock the thickness limitation of particle-shape silver thin
films for near-infrared absorbers.This can be designed by staking graphene and silver thin
film on a substrate through a combination of a graphene transfer method and a magnetron
sputtering technique. We design the stacking of graphene/silver nanoparticle film on a
classical metal-insulator-metal configuration, which consists of a top-layer graphene/silver
nanoparticle layer and a bottom thick silver layer separated by a spacer SiO2 layer. The
experimental analysis of the device points out that nearly 100% absorptance can be achieved
in the near-infrared region.

  Preview abstract

We numerically demonstrate that plasmonic graphene nanoribbons (GNRs) can serve as an atomically thick open-nanocavity for vibrational strong coupling (VSC), exhibiting extraordinary cooperativity in the nanoscale. The behaviors of the molecule-GNR hybrid system are analytically depicted using the temporal coupled mode theory (TCMT), showing good agreement with the numerical simulations. The atomically thick resonators offer a new route alternative to the commonly used Fabry-Perot cavities for VSC.

  Preview abstract

Perovskite quantum dots (PQDs) are a promising candidate for photodetection due to their optical, and electrical characteristics, alongwith cost-effective solution processability. However, their optoelectronic performances hinder by their weak light-matter interaction. Here, we hybridize PQDs with shaped plasmonic gold nanocrystals (AuNCs) and graphene to demonstrate a superior photodetector through a synergetic effect. Our experimental results indicate that shaped AuNCs all contribute to better photodetection behaviors due to trap state passivation and enhanced charge carrier densities with a longer lifetime compared to that of pristine PQDs. In particular, the PQDs/RD-AuNCs/Gr photodetector demonstrated a record-high responsivity among the PQDs/AuNCs/Gr-based electrostatic gate-free photodetectors.

  Preview abstract

We numerically investigate the characteristics of plasmonic merons near a metallic surface, revealing a pivotal height-driven transformation from Neel to Bloch-type. This dynamic transition occurs within a specific height range, marked by rapid evolution. The interplay between plasmonic spin-textures controlled by surface plasmon polaritons in the near field and edge-scattered fields in the far field triggers this phenomenon.

  Preview abstract

We initially employed the surface-initiated solution growth technique to synthesize perovskite nanowires. By using various ratios of methylammonium lead halide solutions, we successfully produced nanowires with halogen-mixed compositions. Analyzing the photoluminescence and X-ray diffraction characteristics provided us with comprehensive insights into the hybrid perovskite composition and the controllable light emission properties. To achieve precise control over the central emission wavelengths, we employed both vapor-phase and solid-phase anion exchange methods. This allowed us to finely adjust the proportions of halogen elements within the perovskite nanowires, opening up promising applications for these nanowires in areas such as light emission and sensing.

  Preview abstract

To realize a stable and widely tunable laser for applications in optical communication and sensing systems, we design and optimize a wavelength tunable laser forming with a gain chip and a silicon-photonics dual-ring resonator as an external cavity. The dual ring resonators have different free spectral ranges to employ the Vernier effect to enlarge the wavelength tuning ranges. The simulation indicates that the dual-ring resonator-based tunable laser achieves a wavelength tuning range of 77.67 nm, with a minimum side-mode suppression ratio (SMSR) exceeding 35 dB and an average SMSR of 43.8 dB.

  Preview abstract

This work employed nanotransfer printing (nTP), a simple method for fabricating plasmonic color filters. We employed e-beam deposition and nTP to transfer the metal array. Furthermore, by undergoing two rounds of nTP, we successfully accomplished the fabrication of a 3D metasurface with a straightforward and efficient approach. The optical properties of the fabricated plasmonic color filters were evaluated through simulation and experiment. We believe that nTP is a promising technique for metallic patterning, offering a viable approach for the fabrication of plasmonic metasurfaces.

  Preview abstract

The electron microscopy techniques for nanofabrication and study of nanomaterials for photonics application are presented. New Zeiss solutions allow not only to produce of periodic nanostructures in different materials, but also to visualize the structure with high resolution during the process of nanofabrication. The benefits of Gemini electronic optics for high quality imaging and Ion-sculptor FIB column for sample preparation and nanostructuring are demonstrated.

  Preview abstract

We explore a solvent engineering approach to enhance the quality and optical performance of quasi-2D perovskite thin films. By optimizing the ratio of γ-butyrolactone (GBL) and dimethyl sulfoxide (DMSO) in the solvent mixture and carefully controlling the timing of antisolvent dripping, we successfully synthesized quasi-2D perovskite thin films based on BA2PbI4 films with a surface coverage exceeding 98%. This method resulted in an increased absorption rate and improved photoluminescence emission. These findings can potentially be applied to enhance the optoelectronic properties of other 2D perovskite materials, making them promising candidates for use in light-emitting devices and energy-harvesting components.

  Preview abstract

This study presents the synthesis and characterization of previously unexplored In6Se7 crystals, a III-VI class compound semiconductor with potential optoelectronic applications. In6Se7 crystals were grown using CVT method with ICl3 as transport agent. Structural analysis and the effects of P content on electrical properties were investigated, providing valuable insights into this field. EDS mapping and TEM confirm the high-quality of In6Se7:P crystals, while XRD and Raman reveal monoclinic crystal structure. In6Se7:P exhibit n-type behavior likely due to P-Se bonds. The work function of P-doped In6Se7 was measured, and P dopants are considered suitable donor-type impurities for future In6Se7 device applications.

  Preview abstract

In recent years, the concept of using metasurfaces integrated liquid crystals to achieve active control of hue has become increasingly important. However, this method lacked the ability to adjust brightness, limiting its practical applicability. In this study, we aim to design three metamaterial perfect absorbers as metasurfaces, combined with a liquid crystal module. These metamaterial perfect absorbers will correspond to one of the primary colors (red, blue, and green) and black, for two different polarization directions. By utilizing the liquid crystal module to rotate the incident light's polarization direction, we can adjust both the displayed hue and brightness.

  Preview abstract

In this study, we propose a novel design for large-area photoconductive emitters using plasmonic contact electrodes. Our optimized design incorporates superlattices made of InGaAs and InAlAs materials, enabling efficient terahertz (THz) generation and detection. By enhancing carrier separation and acceleration within the device, we achieve significantly higher optical-to-terahertz conversion efficiencies compared to conventional designs. Furthermore, we comprehensively analyze the impact of electrode parameters, including individual pairs, emitter density, and exposed semiconductor area, on the emission efficiency. Our findings pave the way for advancements in THz technology, offering promising prospects for various applications in terahertz generation and detection systems.

  Preview abstract

We investigate the bound states in the continuum (BICs) in dielectric metasurfaces consisting of square patches deposited on a dielectric substrate. Symmetric-protected BICs occur at the Brillouin zone center, which are associated with extremely large quality factors and small linewidths. In particular, the BICs are identified as toroidal dipole (TD) modes characterized by the electric or magnetic fields bend into a torus, with the magnetic or electric circling around the surface. Both the electric or magnetic TDs are gathered in the unit cell to form the multiple TD modes.

  Preview abstract

The resonant waveguide gratings (RWGs) with in and out couplers have been demonstrated to perform selective color-filtering and beam steering. However, RWGs with forward design suffers lower efficiency that limit the applications. Here, we design a metasurface which composed of titanium dioxide RWGs on the glass substrate working at red, yellow, green, and blue wavelengths, simultaneously. And we improve the diffraction efficiency by using adjoint-based topology optimization. The diffraction efficiency of simulation is up to 77% with the Q-factor reaching 1367. Such a beam steering device opens a new paradigm for applications, including see-through optical combiners and augmented reality platforms.

  Preview abstract

In this work, we deliberately fabricate a heterogeneous array of Al nanocaps on a wide-bandgap semiconductor of GaN truncated nanocones, and then present a multifunctional plasmonic sensor for excellent UV photodetection and gas sensing. As a UV photodetector, we show maximum responsivity (1.8 × 108 AW-1) and detectivity (1.2 × 1018 Jones) at the resonance wavelength of 355 nm, which is based on our knowledge, the highest detectivity among GaN-based UV photodetectors. As a gas sensor, we detect a gas of NO2, and provide a superior response of 28% and a detection limit of 500 ppb, respectively

  Preview abstract

We demonstrated low temperature operation of GeSn waveguide photodetectors operating in 2µm wavelength band for advanced sensing applications such as quantum computing. Performance parameters such as optical response, dark current, cut off wavelength of fabricated device is analyzed at low temperature which open the avenue of advanced applications of silicon photonics devices in quantum technologies.

  Preview abstract

From the observation of the black pattern in the electroluminescence image under different stored conditions, we verify the degradation mechanism of perovskite light-emitting diodes. Here, we provide an alternative way to suppress device degradation and emphasize the importance of metal electrodes. Finally, we suggest that quai-2D can reduce this degradation of intrinsic properties and point out Ag - stable cathode metal.

  Preview abstract

The development of micro and nanolasers is advancing through innovative concepts like Whispering Gallery Modes (WGMs) and Bound States in the Continuum (BICs). WGMs offer efficient light confinement but limited small radii. BICs, on the other hand, enhance Q factors by suppressing out-of-plane radiations, enabling chip-scale nanolasers with structured light emission, opening new possibilities for photonics applications.

  Preview abstract

We numerically investigate the second-harmonic generation (SHG) efficiency of a silver plasmonic two-wire transmission-line. The intrinsic material property of silver enables greatly extended SHG coherence length between a particular set of propagating surface plasmon modes.

  Preview abstract

Recently, hexagonal WS2 (h-WS2) with triangular heterogeneous defect domains show the promising results in valley polarized emission at room temperature. By illuminating WS2 with circularly polarized light and measuring the circularly polarized emission, the PL intensity is significantly difference at two circularly polarized emission with same circularly polarized light. In this work, we proposed monolayer (h-WS2) shows great selectively valley-polarized photoluminescence (PL) by combining with plasmonic-nanostructures. Chiral plasmonic metasurfaces are proposed combining with h-WS2 to strongly enhance the circular polarized selective of PL.

  Preview abstract

Phase-change materials (PCMs) provide a specific combination of properties. The binary semiconducting chalcogenide Sb2S3 is consider one of the promising candidates, especially its intrinsic high refractive index, low loss and wide bandgap properties, in near infrared (NIR). Here, the Sb2S3 transformation from amorphous to crystal state embedded between the distribute Bragg reflector (DBR) and metal layer. At the interface between DBR and metal layer in specific parameter, Phase-change Tamm plasmon–polariton (PC-TPP) resonance could be produce. The PC-TPP resonance has a 70 nm modulation wavelength. Also, the resonance achieves around 100 nm-shifted in NIR at the proper incident angle.

  Preview abstract

Nanowire (NW) lasers has great potential in the field of optoelectronics. Nevertheless, tunning threshold usually need complicated fabrication process or extra energy doping. The carrier in monolayer WS2 can diffuse into the NW that can decrease the threshold of the NW lasing. Here we propose that put NW on monolayer WS2 and control the carrier density by modulating gating voltage. It indirectly affects the transformation of carrier from WS2 to NW. Eventually achieve the purpose of tuning InP NW lasing.

  Preview abstract

We study thermal emission from a one-dimensional photonic crystal with an ensemble of two-level atoms.
Both light and matter are treated quantumly. The matter is modeled as an ensemble of two-level atoms, where the equilibrium population of electrons is the Fermi-Dirac distribution. The dynamics of photon energy density inside and outside the photonic crystals are investigated. The conditions and evolution of super-Planckian radiation are discussed.

  Preview abstract

Here we theoretically explored the biosensing application of the Rabi splitting (RS) induced by the strong coupling of surface plasmon polaritons (SPPs) and Tamm plasmon states (TPs). Previously, plasmonic biosensors were mostly performed by a pure plasmonic mode. However, we figured out that with the spectral integration method the surface sensitivity in the SPP and TPs generated RS region is about 1.32 times that in the pure SPP region. This indicates that while strong coupling weakened the original SPP, the original TPs split the electromagnetic fields to form new TPs-SPP modes, thereby enhancing the evanescent field for sensing applications.

  Preview abstract

We investigated the influence of mis-orientated GaAs (111)B substrates on the growth of epitaxial I-III-VI2 CuInSe2 chalcopyrite thin films. The epitaxial thin film exhibited several different features due to the availability of step and kink sites. The cmposition of the epitaxial film was in range of Cu-rich to Cu-poor on the identical GaAs (111)B substrate depending on the off-angle. A step flow growth mode was proposed that linear growth in the kink sites along [110] step and subsequently two-dimensional step flow (112) of chalcopyrite grew in Cu-poor region. The influence of off-angle substrate was significant for the epitaxial growth.

  Preview abstract

In this study, oxygen plasma etching was performed to roughen the surface structure of an Al-doped ZnO (AZO) seed layer. The distribution of Ag nanoparticles was optimized to improve the characteristics of a film and facilitate its application as a touch sensing electrode. As the result, the film’s resistance was 3.21 × 10−3 Ω-cm, its SE was 45.04%–52.48%, and its ST error was within 7.44%.

  Preview abstract

In this study, Ga-doped Zinc Oxide (GZO) had been used as material to apply on touch sensing. In addition, touch sensing properties of the GZO thin films are further improved by depositing different GZO layers with the nitrogen-mediated crystallization (NMC) as buffer layers. Finally, the thin film structure as GZO (200 nm)/NMC GZO (100 nm)/ PC plastic substrate was deposited in the N2/Ar flow ratio of 1/8 has optimum touch sensitivity, and is enhanced as 6.12% from 1.046 to 1.110 compared to the pure GZO (300 nm) thin film.

  Preview abstract

In this study, RF magnetron sputtering was used to deposit Zinc Oxide (ZnO) nanofilms and Copper Oxide (CuO) nanostructures, and firstly the sputtering power was adjusted to study the structural changes of ZnO nanofilms surface porosity. By optimizing the process parameters and incorporating the CuO nanostructure, the sensing characteristics of the ZnO thin film can be improved and the lower work temperature CO gas reaction had been done.

  Preview abstract

In this study, radiofrequency (RF) magnetron sputtering was applied in the deposition of a Zinc Oxide (ZnO) thin film, to improve the photoelectric properties of the ZnO thin film, inclined process was used to modify the thin-film deposition process. Specifically, the intermittent number (IN) and intermittent time (IT) were first adjusted to facilitate the formation of the thin film before the inclined fabrication. After the optimal angle of inclination was determined, rapid thermal annealing was used to further optimize the structure of the deposited thin film.

  Preview abstract

Melting methods are used to prepare I-III-VI2 CuInSe2/CnGaSe2 ordered vacancy compounds (OVC). Three pure elements copper, indium or gallium and selenium are put into quartz tubes and sealed, and then melted in a high-temperature furnace. Ternary chalcopyrite crystals of Cupoor Cu1In1.6Se2.8 / OVC Cu1In3Se5 and Cu-poor Cu1Ga1.6Se2.8 / OVC Cu1Ga3Se5 are obtained. The grains sizes of these ternary compounds are larger than 400µm by SEM observation. XRD analysis shows that these compounds have strong (112) preferred orientation. The surfaces of the ordered vacancy compounds Cu1In3Se5 and Cu1Ga3Se5 are composed of (112)A [metal terminated surface] and (112)B [selenium terminated surface].

  Preview abstract

In this research, we investigated the gas sensing behavior of two fluorene-based derivatives at different annealing temperatures. These derivatives were employed as the sensing materials for gas sensors featuring a vertical channel nano-porous diode structure. Our study revealed that these materials exhibited remarkable sensitivity to NO, with a detection limit below 100 ppb. This promising finding suggests their potential application in diverse fields, such as industrial and medical settings.

  Preview abstract

The absorption spectrum of a metal nano-array is mainly determined by the structural shape, size, and environment. In this work, through numerical simulations, we aim to enhance the absorption spectrum using the multilayer hyperbolic metamaterials, thereby reducing the size dependence of the array structure. This approach offers the potential to precisely tune the metal nano-arrays absorption properties, thereby benefiting various applications in sensing and imaging.

  Preview abstract

The reflection spectra presented the effects of attached metal nanoparticles adjacent to the TiO2 nanoparticles. The high refractive index of TiO2 nanoparticles breakdown the main plasmonic resonance modes on Ag nanoparticles and suppresses the main resonance peaks of the Ag nanoparticles. The homogeneously deposited TiO2 nanoparticles randomly scattered the incident light and broadened the absorption peaks of various samples.

  Preview abstract

For quantum photonic applications, such as quantum communication, optical quantum information processing, and metrology, solid-state sources of single-photon emitters are highly needed. We report an effective method for generating single-photon emission in mechanically exfoliated hBN flakes by annealing. We compare the result of nitride-annealing and argon-annealing to identify which type of the defect we induced. The result of single-photon emission shows high stability and brightness. Our results provide an effective method for generating room-temperature single-photon emitters in 2D hBN

  Preview abstract

We study thermal radiation in a cavity. Such a system consists of light and matter. We assume that the matter is in thermal equilibrium and possesses a clearly defined temperature. The matter is modeled as dipoles of which the polarizations are gaussian random numbers and their spectra adhere to the black-body radiation principles. We implement the systems with the finite-difference time-domain (FDTD) method. This approach is flexible regardless of geometries and is advantageous in studying temporal behaviors. We simulate thermal radiation of one-dimensional and two-dimensional cavities. The differences of the temporal dynamics between one-dimensional and two-dimensional cavities are also discussed.

  Preview abstract

We present the synthesis of plasmonic silver nanopopcorns by an one-step solution phase method for the antiobiotic detection of nitrofurazone. The hotspots formed in the nanoscale protrusions and crevices possesses strong electric field to enhance the Raman signal intensity of analyte through electromagnetic mechanism. The produced flexible SERS substrate owns superior detection performance of low limit of detection 1.18×10-9 M and high enhancement factor 2.52×108 for the detection of nitrofurazone.

  Preview abstract

Quantum dot light-emitting diodes (QLEDs) is a promising candidate of new generation for flat-panel displays for its bright and saturated emission colors. In the experiment, the effect of double hole transport layers (HTLs) consisting of poly-TPD and TFB on the performance of blue QLEDs was demonstrated. Compared to the QLED with single hole injection layer of poly-TPD, the QLED with double HTLs was with a turn-on voltage of 3.0 V, a maximum brightness of 121580 cd/m2 and current efficiency of 10.85 cd/A.

  Preview abstract

This study presents a GaN-based metalens designed for dual focusing through asymmetric spin-orbit interaction (A-SOI). We optimize meta-atom parameters to achieve crucial 2π phase convergence, ensuring high diffraction efficiency. Thanks to the merits of the geometric phase, the so-called PB phase, which gives the unit cell another way to manipulate phase under both right and left circular polarization. This metalens exhibits the exceptional ability to focus light at distinct positions on the optic axis. This capability shows significant potential, particularly in the field of high-resolution microscopy, indicating the possibility of advancing imaging technology.

  Preview abstract

The promising hybrid photodetector design was realized through the incorporation of PEDOT:PSS tunnel layer with SiOx/Si nanowires (SiNWs) (Fig.1), which went beyond the intrinsic limitation of band-gap associated photosensing characteristics of conventional Si semiconductors toward revolutionarily turning into wavelength-selective features (Fig.2). The optical simulation results (Fig.3) demonstrate that possibly minimizing the internal reflection of incoming lights, which benefitted the improvement of wavelength-selective photoresponses. We anticipated the design strategy along with detailed explorations on the spectral selectivity of detectors could open up the promising employment of advanced optoelectronic devices, optical communication (Fig.4) and other functional applications.

  Preview abstract

In this study, we investigated a photonic crystal microdisk cavity laser to eliminate the degenerate modes and achieve single-mode lasing action. The lasing properties of the whispering gallery modes including lasing spectral, light-in-light-out curves, and lasing linewidth were characterized in the study. Additionally, we analyzed the lasing linewidth by varying the hole radius to verify the single mode.

  Preview abstract

In conventional microscopes or endoscopes, the depth of information that can be observed from samples is limited. By integrating varifocal metalens into microscope or endoscope systems, observation at different depths of the sample can be achieved, enabling the reconstruction of three-dimensional images. In this work, simulation of the focal-field distribution of varifocal metalens is performed using FDTD simulation software. The simulation results demonstrate that the focal position can be tuned by rotating the relative angle between the component metasurfaces. The present results can be utilized for parameter optimization and pre-manufacturing validation.

  Preview abstract

This study focuses on the destructive etching of semi-insulating 4H-SiC wafers using molten KOH, which were generated by the PVT method. The wafers were then analyzed using optical microscopy to examine defects, surface morphology, and dimensions. The etching depth was measured using a granite measuring stand, while the profile and size of the etch pits were observed using laser scanning confocal microscopy. Through precise control of etching temperature and time, two typical defects, TSD and MP, were confirmed on the industrial-grade semi-insulating 4H-SiC Wafer.

  Preview abstract

The reflection spectra presented the effects of thermal treatment by microwave heating on the samples of fluoride-assisted galvanic replacement reaction (FAGRR) synthesized Au or Ag dendritic nano forests (DNFs) on Si substrate. The samples of dense Au samples presented increased optical reflection after microwave thermal treatment while the Ag samples presented a slight decrease.

  Preview abstract

In this work, we present a THz source of phosphorus doped GeSn photomixer. It can generate continuous-wave.And GeSn in process is much cheaper than III-V group material.The result tell us that GeSn can become a new material for terahertz technology in
the future.


  Preview abstract