Session Index

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