Session Index

We represent AI-designed metasurfaces and three low-cost manufacturing: 1) nanoimprinting with
high-refractive-index dielectric particle embedding resin (PER), 2) bandgap engineering of
hydrogenated amorphous silicon (a-Si:H), and 3) atomic-layer coating on imprinted resin. a-Si,
TiO2, and ZrO2 PERs are used for metasurfaces at infrared (940 nm), visible (532 nm), and
ultraviolet (325 and 248 nm), respectively; measured efficiencies reach 47% (940 nm), 91% (532
nm), 72% (325 nm), and 49% (248 nm). PER metasurfaces with an inverse design provide 3D, fullcolor holography at visible. The bandgap of a-Si:H is engineered to suppress optical losses,
realizing metasurface efficiencies of 42% (450 nm), 65% (532 nm), and 75% (635 nm). We deposit
an atomic layer on resin for 12-inch metasurfaces, achieving measured efficiencies of 61% (450
nm), 78% (532 nm), and 65% (635 nm).

  Preview abstract

Electrically tunable anisotropic optical medium based on nematic liquid crystals for varifocus in augmented reality is investigated. The plane-parallel plates with electrically tunable liquid crystal are applied in a varifocal AR system to solve vergence-accommodation conflict problem. We report a theoretical and experimental study of the influence of anisotropic medium to the imaging in AR system. In experiments, the projected virtual image can be adjusted from 1.3 m to 2.0 m away from the AR system while the thickness of LC plane-parallel plates < 3mm.

  Preview abstract

This research investigates the characteristics of scattered light in AR near-eye systems that employ volume holographic optical elements (VHOE) as waveguide combiners. We examine the potential root causes of scattered light using a hybrid optical simulation approach that combines both ray and wave optics considerations. Our study reveals that, although VHOEs exhibit certain scattering characteristics, the primary contributor to scattered light is the contrast ratio of micro-display panel. Therefore, improving the contrast ratio becomes paramount in the effort to minimizing scattered light effects and elevate the overall AR user experience.

  Preview abstract

Micro-light-emitting diodes (micro-LEDs) with phenomenal advantages are becoming mainstream in today's high-end displays. However, persistent challenges exist in maintaining high image quality and relying excessively on time-consuming mass transfer techniques. To address challenges, firstly, we employ photolithography that enables a high-yield color conversion layer with a full-color ultra-high definition at 2540 PPI. Secondly, in the case of pixel miniaturization, we reduce the aspect ratio of the pixel while incorporating zinc oxide nanoparticles with high thermal conductivity to maintain color fidelity; this enhances pixel structure, reduces color crosstalk, and improves the heat resistance of the color-conversion layer.

  Preview abstract

In this study, we present a blue resonant cavity micro-light-emitting diodes (RC-μ-LED) using staggered InGaN/GaN multiple quantum wells (MQWs), atomic layer deposition passivation, and nanoporous distributed Bragg reflector (NP-DBR). The peak wavelength shifted from 455.31 nm to 449.18 nm with a 6.13 nm blue shift when the current increased from 9 A/cm² to 54 A/cm². The RC-μ-LED exhibited a divergence angle as low as 39.04°.

  Preview abstract

In today’s virtual reality (VR) product, the pancake type has become the mainstream architecture, because the folded type can greatly reduce the overall length. Although the image quality of the pancake type is better than that of the traditional design, its spot size at a wide field of view is still too large compared to the pixel size of high-resolution panels. According to the image quality analysis, lateral chromatic aberration is the leading cause of huge spot size. After adding the diffractive optical element (DOE) in optimization, the lateral chromatic aberration and spot size can be significantly improved.

  Preview abstract

We present an efficient bi-focal meta-lens that converts a linearly polarized incident plane wave (λ=365 nm) into left circular polarized and right circular polarized light focusing on different points. The bi-focal meta-lens is composed of a set of 500 nm-high birefringent AlN nanofins with a near-unity polarization conversion rate. This efficient and UV-transparent AlN bifocal meta-lens demonstrated a high potential for the circular polarization multiplexing in the applications in mask-less photolithography, curing-based 3D printing, and other advancing semiconductor manufacturing and nanotechnology.

  Preview abstract

This study demonstrates a tunable transflective polarization grating device based on cholesteric liquid crystals (CLCs) achieved by electrical control. By applying a low-frequency (30 Hz) pulse voltage, CLCs can be switched from the planar state to the uniformly lying helix (ULH) state. This transition, combined with the periodic alignment structure of the alignment layer, enables switching between transmissive and reflective modes of the polarization grating device with excellent diffraction performance. These results highlight the significant potential for future applications.

  Preview abstract

In this paper, we investigate the polarization aberrations of electrically tunable liquid crystal (LC) mirrors with two kinds of configurations (flat and curved ones). The LC mirrors exhibit spatially-continuous tunable wavefronts. The detailed wavefronts of two LC mirrors are related to angles of incidence, polarization of light, and the alignment direction of LC molecules. The key contribution of this paper is the development and characterization of a tunable liquid crystal mirror. The tunability of polarization aberration of LC mirrors should be able to provide extra parameters for optical engineers to design versatile optical systems.

  Preview abstract

Traditional metalenses designs primarily focus on phase distribution. However, their efficiency was hampered by inherent optical losses in materials like silicon, especially within the visible range, which is crucial for AR/VR applications. Here, we are leveraging the advantages of complex field optimization, taking into account both the scattered phase and amplitude of each meta-atoms. This approach holds the promise of significantly improved efficiency and the potential for real-world applications with scalable production.

  Preview abstract

A nano-photonic metasurface is designed and used to generate abrupt autofocusing (AAF) beam for biomedical applications. The AAF beam offers high intensity contrast and unique focusing. It shows potential for creating miniature laser surgery instruments.

  Preview abstract

In this work we use of the optical topology optimization density model to design achromatic gallium nitride (GaN) metalenses. The goal is to optimize the structure of the metalens to achieve minimal aberration and maximum efficiency with multi-frequency incident light, thereby improving the quality of the lens. We design two experiments to achieve precise deflection for incident light of different frequencies, and enhancing the performance of metalenses when dealing with multi-frequency incident light. The results show that the topology optimization density model can reduce chromatic aberration in GaN metalenses and improve their performance in handling multi-frequency input light.

  Preview abstract

In this work, we design and fabricate cubic-phase metalenses using deep ultraviolet (DUV) photolithography. By employing an intelligent reticle modification flow based neural-network U net architecture, we can increase the resolution and process window of the DUV photolithographic process. Furthermore, nearly vertical etched sidewall profile with a high-aspect ratio of 1:5 has been achieved. As a result, we demonstrate a cubic-phase metalens for computational imaging.

  Preview abstract

Structured light (SL) has been instrumental in 3D imaging. Conventionally used
diffractive optical elements are limited in field-of-illumination. Here, we propose a
metasurface-based SL for wide field-of-view (FoV) 3D imaging. The metasurface-enhanced
SL covers the full 180° FoV, with a high-density ~10K dot array. To this end, the metasurface
is designed by considering the periodic supercell as a kernel function. As a proof-of-concept,
we place face masks and estimate the depth using a stereo matching algorithm. Furthermore,
we scalably fabricate metasurface using the nano-imprint-lithography. Metasurface-driven
structured light promises 3D imaging for autonomous vehicle, robotics, and augmented/virtual
reality systems.

  Preview abstract

Here, we demonstrated humidity-responsive full color nano-pixels with 700nm
resolution using 3D nanoimprinted polyvinyl alcohol (PVA) and disordered silver
nanoparticles (NPs). The nano-pixels are designed as Fabry-Pérot (F-P) structure which is
composed of an aluminum mirror substrate, humidity-responsive PVA spacer, and disordered
silver nanoparticles as top metal layer. The proposed structure has three main merits as
follows. It has 1) high resolution thanks to 3D nanoimprinted PVA technique, and 2)
millisecond-response time (441ms), 3) vivid color generation thanks to disordered silver NPs
which enhance the penetration speed of water molecules into the PVA layer and have highly
absorbing dielectric optical property.

  Preview abstract

Here, we explore the utilization of polyvinyl alcohol (PVA) through a one-step
nanoimprinting technique to create optical security metasurfaces. These metasurfaces exhibit
multiplexed coloration and metaholography. The PVA nanoimprinting achieves a remarkable
resolution of less than 100 nm, with aspect ratios approaching 10. When subjected to
variations in relative humidity, the PVA nanostructures can swell by up to approximately
35.5%, enabling precise manipulation of visible light wavefronts. In this study, we
demonstrate highly secure multiplexed encryption metasurfaces that can reveal, conceal, or
eradicate information based on relative humidity changes, both in an irreversible and
reversible format.

  Preview abstract

TBA

  Preview abstract

Volume holographic optical elements (VHOE) as lightguide components for near-eye displays (NED) can control the propagation direction of input light fields. We establish an optical model to simulate inputting a two-dimensional image, and after passing through the lightguide structure, the angular spectrum distribution of the two-dimensional image can be output. In addition to the information regarding the angular spectrum distribution of the image, the distribution of input light with different wavelengths can also be analyzed simultaneously.

  Preview abstract

This study proposed a 2-D EPE light-guide design based on VHOEs. Compare to traditional structure, the engineering difficulty of the angular multiplexing process is easier. Finally, the light-guide achieves a FOV of 27.2 degrees when used with the LED light source.

  Preview abstract

Currently, automotive high-beam headlights commonly use designs based on reflectors and fisheye lens refraction. It requires a larger fixture size, leading to excessive weight, and suffers from issues such as poor optical efficiency. We propose a Refracting type LSR design for compact automotive High-Beam headlights, utilizing high-power LEDs combined with Liquid Silicone Rubber (LSR) light guid and Aspheric Biconvex lenses to complete the High-Beam headlights module for automotive. On the ECE R112B surface has been improved to 50.9%. Imax is 81506.3 cd, and the H-V point is 80075.1 cd. Achieving lightweight and miniaturization while complying with ECE R112B.

  Preview abstract

This study combines angle multiplexing with near-eye display technology and light field design to address the conflict of visual accommodation and convergence. By recording the wavefront of a micro-lens system with different focal lengths on a holographic plate, the effects of angular magnification and the Bragg condition of volume holography are used to select specific sub-scenes.

  Preview abstract

In recent times, the metaverse has been rapidly developing, aiming to create a cyberpunk-inspired 3D virtual world network with a strong focus on social connections. Current limitations stem from hardware and sensor constraints for real-time interaction. In this article, we introduce a novel nanolaser technology capable of miniaturizing laser components below the diffraction limit, significantly increasing the density of laser units. By enhancing the density of laser arrays, they have the potential to be used in laser displays, enabling a more realistic and personalized modeling of the virtual world, ultimately delivering an enhanced user experience.


  Preview abstract

The study uncovers significant insights into the impact of interval time on laser ablation processes. Remarkably, the baseline of interval time(bit)/√2 group demonstrates higher mean laser ablation quality values, reb, than the bit and bit/∜2 group, despite the same energy levels. Notably, a striking peak mean reb occurs at 70.7 seconds interval time and 0.378 mJ energy level. Through k-means learning, k is 5, the representative equation emerges as the superior regression mode for fitting the cluster points. An impressive coefficient of determination, R2, value of 0.9368. Furthermore, a distinctive trend reveals a decrease in Δreb with rising energy levels.

  Preview abstract

This paper presents a machine learning-based eye-tracking model for head-mounted light field displays. Using a camera to capture visible light RGB images, the model predicts gaze points from human eye inputs through a neural network. This work addresses eyetracking within light field applications.

  Preview abstract

An AR display is integrated with a full holographic curved waveguide combiner. Ghosting phenomena can occur in curved waveguides due to the path of the incident light. To design efficiently and to accurately calculate the dimensions of Volume Holographic Optical Elements (VHOE) to avoid such ghosting, it is necessary to establish a mathematical model. This model uses the ABCD matrix to calculate the position of total internal reflection each time when the light travels through the waveguide.

  Preview abstract

As applying volume holographic optical elements (VHOEs) on the light guide in the see-through in the mixed-reality (MR) glasses, the color breaking in different view angles has somehow become a serious drawback in the practical applications and induces urgent need to be solved. In this work, we extensively explored with the color breaking effect according to the wavelength --dependent and angle--dependent diffraction efficiency spectrum of VHOEs for MR displays. As considering the color metamerism, a certain possible illumination light sources for reduction of the color breaking within FOVs can then be concluded. Some corresponding experiments are also performed for verification.

  Preview abstract

This study presents the development of a near-eye display with a field-of-view extension array system. It is composed of three volume holographic optical elements and light guides. Due to the volume holographic optical elements' ability to record interference fringes, we move the position of the microscopic lens to create interference fringes with varying focal lengths. This creates different focal lengths of the volume holographic optical elements, thus generating varying levels of field-of-view magnification.

  Preview abstract

Two-dimensional transition metal dichalcogenides (2D TMDCs) have emerged as promising semiconductor materials due to their remarkable properties, including an ultrathin atomic layer structure and unique valley-spin characteristics. These materials have the potential to revolutionize semiconductor technology beyond silicon. However, their production methods, such as chemical vapor deposition (CVD) and mechanical exfoliation, have limitations. To address these challenges, this study explores the application of deep learning, specifically a Transformer model, for the automated identification of monolayer 2D TMDCs. The novel approach leverages semantic representations to enhance accuracy and adaptability, providing a promising solution for the mass production of high-quality 2D TMDCs.

  Preview abstract

A metalens is an ultrathin, flat lens made from metasurface that manipulates light and offers compactness and aberration correction. Though there has not been any studies on the metalens disclosure for optical distortion optimization. Here, we propose that it can be addressed by co-optimizing the distortion and the optical performance (MTF/focusing efficiency) in the wide-angle metalens(field of view 160°). A single-element wide-angle metalens with correction of f-theta distortion will be particularly optimized. It assists in enlarging the pixels per degree (PPD) at the image corner.

  Preview abstract

In previous publication, we design a liquid crystal (LC) lens set consisting of three polarization switching LC lenses for varifocal images and vision corrections with fast response time. We demonstrate AR and VR systems by adopting the LC lens set to solve VAC as well as vision problem. However, there is some scattering at the edge of the lens due to the excessive thickness. It leads to a decrease in the effective aperture size and field of view. For increasing the aperture size, we conducted experiments to optimize the polarization-switching LC lens.

  Preview abstract

Recent advances in deep learning have opened up exciting possibilities in exploring 2D materials for photonic devices, known for their unique light emission and modulation properties. However, the manual identification process using optical microscopy is time-consuming. To address this, we leveraged the power of deep learning with Mask-RCNN, a state-of-the-art AI model. Training on a curated dataset of 100 labeled 2D material images, we obtained encouraging results. This automated approach offers an efficient solution, eliminating labor-intensive inspections and accelerating the development of 2D materials in photonics applications.

  Preview abstract