Microring resonators, due to their ability to enable robust strong light–matter interactions within their structures, have garnered substantial interest for their utility in sensing applications, particularly in the realm of gas detection. However, there is an inherent trade-off between a microring resonator's quality factor and confinement factor in the air, making it difficult to balance them. Here, we demonstrate a novel solution with a suspended nanomembrane silicon (SNS) microring resonator. This resonator has ultrathin sub-wavelength thicknesses (0.02–0.03λ), which breaks the trade-off, offering not only a high intrinsic quality factor of 6 × 105 but also an extraordinarily large confinement factor of ∼80% in the air at mid-infrared wavelengths. As a proof-of-concept demonstration, we applied the SNS microring resonator for CO2 gas sensing, exhibiting a sensitivity over 10 times higher than conventional silicon resonators and a large dynamic sensing range spanning from 0% to 100% with a high resolution of better than 4% and chemical specificity. By virtue of its excellent properties, the SNS microring resonator has the potential to open new possibilities for the development of unprecedented nanophotonic integrated circuits, with a broad range of applications in on-chip sensing scenarios.

中文翻译：

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具有超薄亚波长厚度的高 Q 硅微环谐振器，用于灵敏气体传感

微环谐振器由于能够在其结构内实现强大的强光-物质相互作用，因此在传感应用中的实用性引起了人们的极大兴趣，特别是在气体检测领域。然而，微环谐振器的品质因数和空气中的限制因数之间存在固有的权衡，因此很难平衡它们。在这里，我们展示了一种采用悬浮纳米膜硅 (SNS) 微环谐振器的新颖解决方案。该谐振器具有超薄的亚波长厚度（0.02–0.03λ），打破了这种权衡，不仅提供了 6 × 105 的高内在品质因数，而且在中频空气中还提供了 ∼80% 的超大限制因子。 -红外波长。作为概念验证演示，我们将 SNS 微环谐振器应用于 CO2 气体传感，其灵敏度比传统硅谐振器高 10 倍以上，动态传感范围从 0% 到 100%，分辨率更高低于 4% 和化学特异性。凭借其优异的性能，SNS微环谐振器有可能为前所未有的纳米光子集成电路的发展开辟新的可能性，在片上传感场景中具有广泛的应用。