A long-wave infrared (LWIR) on-chip gas sensor based on subwavelength grating waveguide is proposed. By optimizing the grating structural parameters, the corresponding slow-light region is overlapped with the absorption spectrum of methane, which can greatly improve the light–gas interaction to achieve excellent sensing performance. The presented waveguide gas sensor is designed to operate at the wavelength of 7.70 μm, which corresponds to the methane absorption peak in the LWIR and exhibits a high slow-light enhancement factor of 7.514. The related sensitivity and limit of detection are, respectively, 26.54393 and 0.1327 ppm.

中文翻译：

---

基于亚波长光栅波导的片上长波红外气体传感器

提出了一种基于亚波长光栅波导的长波红外（LWIR）片上气体传感器。通过优化光栅结构参数，使相应的慢光区域与甲烷的吸收光谱重叠，可以大大改善光气相互作用，实现优异的传感性能。所提出的波导气体传感器设计在 7.70 μm 波长下工作，该波长对应于长波红外中的甲烷吸收峰，并表现出 7.514 的高慢光增强因子。相关灵敏度和检测限分别为 26.54393 和 0.1327 ppm。