晶体AlGaAs镜面涂层中的光双折射效应
Photo-birefringent effects in crystalline AlGaAs mirror coatings
AI总结：
研究晶体GaAs/AlGaAs涂层中双折射的光致变化，发现双光子或单光子过程主导，并通过外部照明平衡光热光响应来降低噪声。
摘要：
与传统的介质涂层相比，高反射晶体$GaAs/Al_{0.92}Ga_{0.08}As$涂层表现出降低的布朗噪声。然而，几个超稳定激光系统观察到额外的噪声源，阻碍了频率稳定性预期改进的实现。这些额外的噪声源与涂层的双折射及其被腔内光的修改有关。双折射的起源尚不明确，其通过光照的修改也仍未得到解释。在这里，我们利用室温下的光学腔，对腔内光以及不同波长均匀照明下双折射的稳态和瞬态修改进行了广泛研究。我们发现了一个统一的描述，表明对于低于GaAs带隙的光子能量，主要是一个双光子过程，而在更高能量下则是单光子过程。添加外部照明可以通过平衡镜面的光热光响应和光双折射效应，在更有利的低腔内功率下减少由激光功率波动引起的噪声。
英文摘要：
High-reflective crystalline $GaAs/Al_{0.92}Ga_{0.08}As$ coatings show reduced Brownian noise compared to conventional dielectric coatings. However, several ultra stable laser systems observed additional noise sources that hinder the realization of the expected improvements in frequency stability. These additional noise sources are related to the birefringence of the coatings and its modification by intracavity light. The origin of the birefringence is not yet well understood and its modification via illumination remains unexplained. Here we present an extensive study on the steady-state and transient modification of the birefringence by intracavity light and by uniform illumination at various wavelengths using an optical cavity at room temperature. We find a unified description that suggests a primary two-photon process for photon energies below the bandgap of GaAs, or a single-photon process at higher energies. Adding external illumination allows to reduce noise induced by laser power fluctuations by balancing the photo-thermal-optic response of the mirrors and the photo-birefringent effect at a more favorable low intracavity power.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
