Session Index

We show some methods for optical designing metalenses that deal with the optimal transfer of light energy, i.e. for light concentration and illumination applications. Owing to its compactness, flatness, and high design flexibility, metasurface-based flat optics may solve some problems in the nonimaging optics field, which deals with light concentration and illumination. We explain the latest advances on this topic. We discuss two algorithms for uniform illumination design with metasurfaces: ray mapping method, and Monge–Ampere equation method. And we discuss the string method for efficient light concentration with flat optics.

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Near-field radiative heat transfer (NFRHT) between different materials is crucial for near-field applications. A groundbreaking achievement demonstrates near-field thermal radiation produced through the interaction of surface phonon polaritons (SPhPs) with magnetic dipole resonances. Both simulation and experiments affirm that silicon (Si) particles can outcouple energy with polar materials' SPhPs within the near-field range, subsequently scattering electromagnetic energy into the far field. Spin-coating with Si particles emerges as a simple, low-cost, and non-destructive method to effectively increase surface emission, holding potential for far-field applications across various sizes of polar materials.

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This research presents a novel approach to creating a key component for a nearinfrared spectrometer with wavelength tunability. The core component is based on a liquid
crystal (LC)-in-cavity structure, forming a hybrid photonic crystal (PC). To investigate the
temperature-tunable defect-mode resonance peaks in the cell, we measured and simulated
temperature-dependent birefringence of the LC used as the defect layer. Our finding illustrates
the behavior of wavelength shift of the resonance peaks as the temperature rises, with blueshift
and redshift observed in distinct temperature ranges. The designed PC/LC structure emerges as
an attractive candidate for spectrometer and optical communication applications.

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Ultra-high N-type chiral photonic crystals (CPC) have recently emerged as a breakthrough in photonics. With an exceptionally large number of periods (N), CPC exhibits extraordinary optical properties, including giant optical polarization rotation and dynamic tunability. This article explores the unique capabilities of CPC in high-transmission spectral regions and its potential applications in optical communications and ultrafast laser technology. The prospects of ultra-high N-type CPC are discussed, highlighting its impact on polarization manipulation of ultrashort laser pulses and dynamic polarization control of sub-picosecond laser pulses.

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In contour measurement technology, fringe projection offers non-contact advantages and widespread application. This paper presents a method using the five-step phase-shifting approach to reconstruct 3D profiles of small objects. Its advantage lies in high tolerance for phase errors and accurate measurements. Precision is vital for fringe phase in profilometers. This study utilizes tailored transmissive masks to project nearly perfect sine wave fringes, followed by Fourier filtering and averaging to enhance fringe accuracy.

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In this study, we investigate the lateral luminance of long-distance solid-state lighting projection lamps. The production of long-distance projection lights is arranged in a 4×4 array, and the projection distance can reach 4.17 km. Using 25 sets of projection lights, the projection distance can be extended up to 20 km. Experiments indicate that different horizontal placements will impact the short-range visual effect, whereas there is no discernible difference at long distances. Altering the placement of the projection lamps does not affect their visual contrast over long distances.

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Extensive investigation reveals the dynamic evolution of cholesteric helical self-assembly and defect formation, with electric fields at different frequencies effectively eliminating unremovable defects and controlling helix alignment. A dual-frequency field assembly technique enables stable, well-aligned cholesteric liquid crystals of unprecedented thickness, offering compactness, high transmission, dynamic tunability, large polarization rotation, and versatile switching/modulation possibilities for ultrafast and continuous-wave lasers across visible, near-infrared, and mid-infrared regimes.

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