Photothermal transfer function of dielectric mirrors for precision measurements
Photothermal transfer function of dielectric mirrors for precision measurements
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DOI：
10.1103/physrevd.91.023010
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发表时间：
2015-01-26
影响因子：
5
通讯作者：
Ballmer, Stefan W.
中科院分区：
文献类型：
--
作者：
Ballmer, Stefan W.
以镀膜设计为输入，计算了从入射到介质镜的吸收功率到有效镜位的光热传递函数。发现对于对应于可与涂层厚度相当的扩散长度的频率，该效应在幅度和符号上改变。计算了用于Advanced LIGO的掺钛Ta2O5：SiO_2涂层和晶态Al_xGa_(1-x)As涂层的传递函数。高频下传递函数的形状是有效吸收深度的灵敏指标，为区分涂层内部吸收和表面污染相关吸收提供了一个潜在的有力工具。光热效应的符号变化也可能有助于稳定基于辐射压力的光学机械系统。还提供了对先前公布的热光噪声估计的高频修正。最后，对微调AlxGa1-xAs涂层中的热光噪声消除的质量进行评估需要本文所做的详细的热流分析。
The photothermal transfer function from absorbed power incident on a dielectric mirror to the effective mirror position is calculated using the coating design as input. The effect is found to change in amplitude and sign for frequencies corresponding to diffusion length comparable to the coating thickness. Transfer functions are calculated for the Ti-doped Ta2O5 : SiO2 coating used in Advanced LIGO and for a crystalline AlxGa1-xAs coating. The shape of the transfer function at high frequencies is shown to be a sensitive indicator of the effective absorption depth, providing a potentially powerful tool to distinguish coating-internal absorption from surface contamination related absorption. The sign change of the photothermal effect could also be useful to stabilize radiation pressure-based optomechanical systems. High frequency corrections to the previously published thermo-optic noise estimates are also provided. Finally, estimating the quality of the thermo-optic noise cancellation occurring in fine-tuned AlxGa1-xAs coatings requires the detailed heat flow analysis done in this paper.