In this article, we present an ultrahigh-Q cavity at terahertz (THz) frequencies. The designed cavity is built on a low-loss suspended silicon (Si) waveguide. The substrate removal under the waveguide and the use of optimized deep reactive ion etching processing are the main reasons for observing very low losses of this design α <; 0.09 dB/mm. This very low-loss behavior of this designed platform is also demonstrated by the measurement of a one-dimensional photonic wire crystal cavity with Q > 18000. Different cavity layouts are adjusted in order to maximize the transmittance while maintaining high Q. A design with reduced number of etched crystal holes achieve Q > 1500 and high transmittance T > 70%. These structures are presented at sub-mm waves (around 600 GHz) for the design of a gas sensor in this frequency region, but the principles can be scaled and redesigned for other frequencies in the THz band.

中文翻译：

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低损耗悬浮硅平台上的高 Q 太赫兹光子晶体腔


在本文中，我们提出了太赫兹 (THz) 频率的超高 Q 腔。设计的腔体建立在低损耗悬浮硅 (Si) 波导上。波导下的衬底去除和优化的深度反应离子蚀刻处理的使用是观察到该设计α<损耗非常低的主要原因； 0.09 分贝/毫米。该设计平台的这种非常低的损耗行为也通过 Q > 18000 的一维光子线晶体腔的测量得到证明。调整不同的腔布局，以便在保持高 Q 值的同时最大化透射率。减少蚀刻晶体孔的数量，实现 Q > 1500 和高透射率 T > 70%。这些结构以亚毫米波（约 600 GHz）呈现，用于设计该频率区域的气体传感器，但其原理可以针对太赫兹频段的其他频率进行扩展和重新设计。