AI 中文总结
本研究提出将超表面置于布拉格反射镜下方的混合反射镜设计，可降低光学损耗与涂层布朗噪声，提升角度容差，为精密光腔应用提供了可行方案。
AI 中文摘要
我们提出一种混合反射镜设计，将嵌入式超表面置于布拉格反射镜下方，结合超表面反射镜的低涂层布朗噪声与传统多层涂层的低光学损耗。与此前将超表面置于输入表面的混合设计不同，本设计将其置于布拉格堆下方，减少了入射到易损耗谐振层的光场。针对工作波长为1064nm的设计，我们表明这可使吸收率从纯超表面的24ppm降至混合结构的7ppm。我们引入了一种通用方法，用于计算任意耦合强度下混合超表面-多层反射镜的涂层布朗噪声，将先前方法扩展为相干结合光束尺度的平均场贡献与超表面的周期性亚波长尺度响应。将此方法应用于我们的设计，发现其布朗噪声振幅谱密度相较于等效反射率的布拉格反射镜降低了1.6倍。最后，我们表明该设计比纯超表面反射镜具有更高的角度容差，在1度的角度范围内保持更高的反射率。本研究为将低噪声超表面反射镜纳入精密光腔提供了实用路径，同时最小化了光学损耗和角度敏感性。
英文摘要
We propose a hybrid mirror design that places an embedded metasurface beneath a Bragg reflector, combining the low coating Brownian noise of metasurface mirrors with the low optical loss of conventional multilayer coatings. Unlike previous hybrid designs, which place the metasurface at the input surface, our design positions it below the Bragg stack, reducing the optical field incident on the loss-prone resonant layer. For a design operating at 1064 nm, we show that this reduces absorption from 24 ppm for a bare metasurface to 7 ppm for the hybrid. We introduce a general method for calculating the coating Brownian noise of hybrid metasurface-multilayer mirrors at arbitrary coupling strength, extending prior methods to coherently combine a beam-scale mean-field contribution with the periodic, sub-wavelength-scale response of the metasurface. Applying this to our design, we find a reduction in Brownian noise amplitude spectral density relative to an equivalent-reflectance Bragg mirror by a factor of 1.6. Finally, we show that this design has higher angular tolerance than a bare metasurface mirror, maintaining higher reflectance over an angular range of 1 degree. This work provides a practical path towards incorporating low-noise metasurface mirrors into precision optical cavities, while minimizing optical loss and angular sensitivity.
Comments11 pages, 6 figures
