Multi‐Objective Inverse Design of a Dual‐Narrowband Thermal Emitter for Optical Gas Sensing

ABSTRACT Spectrally selective narrowband thermal emitters with high‐temperature stability are critical infrared sources for advanced gas sensing. However, conventional Tamm‐plasmon narrowband thermal emitters are commonly implemented as distributed Bragg reflectors on thin metal layers, which can restrict spectral tunability and complementary metal–oxide–semiconductor (CMOS) compatibility. Here, we propose a cost‐effective, CMOS‐compatible, lithography‐free, wafer‐scale aperiodic dual‐narrowband thermal emitter. Optimized via a multi‐objective inverse design framework, the emitter consists of an aperiodic Si/SiO 2 dielectric multilayer deposited on a TiN refractory conductive ceramic film. Experimental results demonstrate that the fabricated sample exhibits two selective emission peaks at 3.26 and 6.30 μm, matching the characteristic absorption bands of CH 4 and NO 2 , respectively. In addition, the emitter maintains its dual‐narrowband spectral response after heating to 693 K. In practical gas‐sensing tests, the dual‐narrowband emitter achieved 12.2‐ and 13.5‐fold improvements in relative sensitivity for CH 4 and NO 2 detection, respectively, compared with a conventional broadband blackbody source. This work provides a scalable refractory infrared source for spectrally selective optical gas sensing.