Li Kunye, Liang Yuhao, Liu Yuxin, Lin Yu-Sheng
School of Electronics and Information Technology, Sun Yat-Sen University, 510006, Guangzhou, China.
School of Chemistry, Sun Yat-Sen University, 510006, Guangzhou, China.
Microsyst Nanoeng. 2025 Jan 8;11(1):2. doi: 10.1038/s41378-024-00851-w.
In conventional nondispersive infrared (NDIR) gas sensors, a wide-spectrum IR source or detector must be combined with a narrowband filter to eliminate the interference of nontarget gases. Therefore, the multiplexed NDIR gas sensor requires multiple pairs of narrowband filters, which is not conducive to miniaturization and integration. Although plasmonic metamaterials or multilayer thin-film structures are widely applied in spectral absorption filters, realizing high-performance, large-area, multiband, and compact filters is rather challenging. In this study, we propose and demonstrate a narrowband meta-absorber based on a planar metal-insulator-metal (MIM) cavity with a metallic ultrathin film atop. Nearly perfect absorption of different wavelengths can be obtained by controlling the thickness of the dielectric spacer. More significantly, the proposed meta-absorber exhibits angle-dependent characteristics. The absorption spectra of different gases can be matched by changing the incident angle of the light source. We also preliminarily investigate the CO gas sensing capability of the meta-absorber. Afterward, we propose a tunable meta-absorber integrated with a microelectromechanical system (MEMS)-based electrothermal actuator (ETA). By applying a direct current (DC) bias voltage, the inclination angle of the meta-absorber can be controlled, and the relationship between the inclination angle and the applied voltage can be deduced theoretically. The concept of a tunable MEMS-based meta-absorber offers a new way toward highly integrated, miniaturized and energy-efficient NDIR multigas sensing systems.
在传统的非色散红外（NDIR）气体传感器中，宽光谱红外源或探测器必须与窄带滤波器相结合，以消除非目标气体的干扰。因此，复用式NDIR气体传感器需要多对窄带滤波器，这不利于小型化和集成。尽管等离子体超材料或多层薄膜结构在光谱吸收滤波器中得到了广泛应用，但实现高性能、大面积、多波段和紧凑型滤波器仍具有相当大的挑战性。在本研究中，我们提出并展示了一种基于平面金属-绝缘体-金属（MIM）腔且顶部有金属超薄膜的窄带元吸收器。通过控制电介质间隔层的厚度，可以获得不同波长的近乎完美吸收。更重要的是，所提出的元吸收器具有角度依赖性特征。通过改变光源的入射角，可以匹配不同气体的吸收光谱。我们还初步研究了元吸收器对一氧化碳气体的传感能力。之后，我们提出了一种与基于微机电系统（MEMS）的电热致动器（ETA）集成的可调谐元吸收器。通过施加直流（DC）偏置电压，可以控制元吸收器的倾斜角度，并且可以从理论上推导出倾斜角度与施加电压之间的关系。基于可调谐MEMS的元吸收器概念为实现高度集成、小型化和节能的NDIR多气体传感系统提供了一种新途径。
