Session Index

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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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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.

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