Title: Phase-matched Deep Ultraviolet Chiral Bound States in the Continuum Metalens Show Chinese title

Title: 相位匹配的深紫外手性连续态中的金属透镜

Abstract: Coherent light sources in deep ultra-violet (DUV) is essential for various applications such as biomedical imaging and biosensing. Nonlinear crystals (NLCs) generate DUV light, but limited by its bulky thickness, low transparency, and strict narrowband phase-matching conditions. Demonstrating compact, broadband, chiral, and focused DUV light integrated device is elusive. In this work, we present the first demonstration of chiral DUV third harmonic generation (THG) in a dielectric metasurface made from crystalline silicon (c-Si) of compact thickness 400 nm. Metasurface supports chiral bound states in the continuum resonance at fundamental wavelength 800 nm with experimental high Q-factor of 130 and modal phase-matched plasmonic resonance at the third harmonic wavelength for efficient THG. Generating DUV-THG power is up to 12 nW using peak power of 15 GW/cm2. Furthermore, we developed a nonlocal metalens operating in DUV for focusing the chiral DUV-THG using the same chiral BIC cavity and phase-gradient approach. Our platform creates efficient, ultracompact, and multifunctional integrated devices for future integrated DUV nanophotonics devices in MedTech, imaging, and advanced manufacturing. Show Chinese abstract

Abstract: 相干深紫外（DUV）光源对于生物医学成像和生物传感等各种应用至关重要。非线性晶体（NLCs）产生DUV光，但受限于其体积大、透明度低以及严格的窄带相位匹配条件。展示紧凑、宽带、手性和聚焦的DUV光集成器件仍然很困难。在本工作中，我们首次展示了在由厚度为400 nm的晶体硅（c-Si）制成的介质超表面中手性DUV三次谐波生成（THG）。超表面在基本波长800 nm处支持手性连续体中的束缚态共振，实验测得的高Q因子为130，并在三次谐波波长处支持模态相位匹配的等离子体共振，以实现高效的THG。使用峰值功率为15 GW/cm²，生成的DUV-THG功率高达12 nW。此外，我们开发了一种在DUV下工作的非局部透镜，利用相同的手性BIC腔和相位梯度方法来聚焦手性DUV-THG。我们的平台为未来MedTech、成像和先进制造领域的集成DUV纳米光子学器件创造了高效、超紧凑和多功能的集成器件。