Hydrogenated amorphous silicon (a‐Si:H) is known for exhibiting light‐induced metastable properties that are reversible upon annealing. While these are commonly associated with the well‐known deleterious Staebler–Wronski effect in the field of thin‐film silicon solar cells, the associated changes in optical properties have not been well studied. Emerging reconfigurable photonic devices and applications can benefit from metastable optical properties where two states of the material are reversibly accessible without the need for continuous stimulation. The study demonstrates a light‐induced 0.3% increase of the metastable refractive index of a‐Si:H that is reversed upon annealing over several cycles using a highly sensitive Fabry–Pérot interferometric technique. Utilizing this technique, a metastable optical switch based on a micro‐ring resonator is demonstrated with reversible distinct switching states separated by 0.3 nm between the light‐soaked and annealed states, a switching extinction exceeding 20 dB and an unchanged Q‐factor, suggesting no excess discernible optical loss. Furthermore, metastable strain changes in a‐Si:H‐based freestanding membrane structures are linked to the observed metastable optical properties and present a possible route to stable photonic devices. Our proof‐of‐concept demonstration showcases a‐Si:H‐based reconfigurable photonics that support multiple purpose photonic integrated circuits, reconfigurable metamaterials, and advanced optomechanical devices.

中文翻译：

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可重构光子学在氢化非晶硅中的亚稳态折射率操纵

氢化非晶硅（a-Si：H）表现出光诱导的亚稳态特性，退火后可逆。尽管这些通常与薄膜硅太阳能电池领域众所周知的有害的Staebler-Wronski效应有关，但尚未对光学性能的相关变化进行深入研究。新兴的可重配置光子器件和应用可受益于亚稳的光学特性，在这种特性中，材料的两个状态可以可逆地访问，而无需连续刺激。这项研究表明，使用高度敏感的Fabry-Pérot干涉技术，经过数个循环的退火，a-Si：H的亚稳态折射率会因光诱导而增加0.3％。利用这项技术Q因子，表明没有明显的光学损失。此外，基于a-Si：H的独立膜结构中的亚稳态应变变化与观察到的亚稳态光学特性有关，并为稳定光子器件提供了可能的途径。我们的概念验证演示展示了基于Si：H的可重构光子技术，该技术支持多用途光子集成电路，可重构超材料和先进的光机械设备。