We present an ultrathin metasurface working as both a highly reflective wavelength-selective mirror and a high transmittance output coupler for a semiconfocal Fabry-Perot cavity. The numerically optimized 2-μ m-thick metasurface achieves a peak reflectivity of R = 99.35% at ω₀ = 94 GHz and peak transmittance of T ≈ 90% at the fourth harmonic (4ω₀). Experimental results show that the metasurface FP cavity exhibits comparable quality factors to cavities enclosed by either a copper mirror or Bragg grating mirror. Our work highlights the potential for ultrathin metasurfaces to function as frequency selective mirrors in millimeter or terahertz wave cavities for various applications, such as nonlinear terahertz wave generation, material characterization, and imaging.

中文翻译：

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适用于毫米/太赫兹波法布里-珀罗腔的超薄超表面波长选择镜

我们提出了一种超薄的超表面，同时用作半共面法布里-珀罗腔的高反射波长选择镜和高透射率输出耦合器。的数值优化2- μ微米厚的超颖表面达到的峰值反射率- [R = 99.35％在ω ₀的= 94 GHz和峰的透射率Ť在第四谐波（4≈90％ω ₀）。实验结果表明，超表面FP腔具有与铜镜或布拉格光栅镜所包围的腔相当的品质因数。我们的工作强调了超薄超颖表面在毫米波或太赫兹波腔中用作频率选择镜的潜力，可用于各种应用，例如非线性太赫兹波的产生，材料表征和成像。