金属-电介质超材料中的二阶非线性能否为难以捉摸的光子时间晶体铺平道路？
Can Second-Order Nonlinearity in Metal-Dielectric Metamaterials Pave a Way Toward Elusive Photonic Time Crystals?
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中文总结 AI 辅助
研究探讨金属-电介质超材料中二阶非线性能否助力光子时间晶体实现。提出利用ε近零半导体-银超材料的超快二阶非线性的平台，通过低损耗和偏振选择性泵浦，在特定泵浦功率下可打开宽动量带隙并实现净参量增益，为光学光子时间晶体实现提供途径。
中文摘要 AI 辅助
虽然大量理论工作致力于时变光子学，但光学范围内的实际实现几乎完全依赖于透明导电氧化物，其受限于速度慢和高损耗。为绕过这些限制，本文提出利用ε近零半导体-银超材料中的超快二阶非线性的替代平台。由于银中相对低损耗和偏振选择性泵浦，超低泵浦吸收防止热降解，同时探针吸收足够低以允许信号检测所需的多周期相互作用长度。研究发现，泵浦功率为数百GW/cm2时可打开数十%的宽动量带隙并实现时间上的净参量增益，为在光学范围实现光子时间晶体提供了有力途径。
英文摘要
While a tremendous amount of theoretical work has been dedicated to time-varying photonics, practical implementation in the optical range has relied almost exclusively on transparent conductive oxides , which remain severely constrained by being slow and highly lossy. To bypass these limitations, I propose an alternative platform utilizing ultrafast second-order nonlinearities within an epsilon-near-zero semiconductor-silver metamaterial. Due to the relatively low loss in silver and polarization-selective pumping, ultra-low pump absorption prevents thermal degradation, while absorption of the probe is sufficiently low to simultaneously permit the multi-cycle interaction lengths necessary for signal detection. I find that with pump powers of 100s of GW/cm2 one can open a wide momentum bandgap of tens of percents and achieve net parametric gain in time, offering a robust pathway to realizing photonic time crystals in optical range.
