Vernier effect has been captivated as a promising approach to achieve high-performance photonic sensors. However, experimental demonstration of such sensors in mid-infrared (MIR) range, which covers abundant absorption fingerprints of molecules, is still lacking. Here, we report Vernier effect-based thermally tunable photonic sensors using cascaded ring resonators fabricated on the silicon-on-insulator (SOI) platform. The radii and the coupling gaps in two rings are investigated as key design parameters. By applying organic liquids on our device, we observe an envelope shift of 48 nm with a sensitivity of 3000 nm/RIU and an intensity drop of 6.7 dB. Besides, our device can be thermally tuned with a sensitivity of 0.091 nm/mW. Leveraging the characteristic molecular absorption in the MIR, our work offers new possibilities for complex index sensing, which has wide applications in on-chip photonic sensors.

中文翻译：

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使用绝缘体上硅级联环的基于游标效应的可调谐中红外传感器

游标效应已成为实现高性能光子传感器的一种有前途的方法。但是，仍缺乏对中红外（MIR）范围的传感器进行实验演示，该传感器涵盖了分子的大量吸收指纹。在这里，我们报告了使用在绝缘体上硅（SOI）平台上制造的级联环形谐振器的基于Vernier效应的热可调光子传感器。研究两个环的半径和耦合间隙作为关键设计参数。通过在我们的设备上应用有机液体，我们观察到了48 nm的包络线偏移，灵敏度为3000 nm / RIU，强度下降了6.7 dB。此外，我们的设备可以进行热调谐，灵敏度为0.091 nm / mW。利用MIR中的分子吸收特性，我们的工作为复杂的指数传感提供了新的可能性，