A High‐Resolution Miniaturized Mid‐Wave Infrared Spectrometer Operating at Room Temperature

ABSTRACT Spectroscopic analysis in the mid‐wave infrared (MWIR) region plays a crucial role in scientific research, industry, and medicine. Conventional benchtop spectrometers fail to meet the increasing demand for in situ and immediate measurements. The miniaturization of MWIR spectrometers is hindered by the scarcity of high‐performance room‐temperature detectors and compatible response‐tunable strategies. In this work, we report a room‐temperature miniaturized reconstructive MWIR spectrometer based on a PbSe detector line array integrated with a Fabry–Pérot microcavity array. Combined with spectral reconstruction algorithms, the device can operate across a wide wavelength range of 2.5–4.25 µm, achieving a spectral resolution of 6.8 nm with one‐tenth the cost of the commercial product (resolution: ∼15 nm), far surpassing the latest miniaturized MWIR spectrometers. Through clearly distinctive imaging of two eye‐indistinguishable organic liquids, its powerful material recognition capability is confirmed. Moreover, the device achieves quantitative detection of triglyceride over a concentration range from 0.067 to 0.403 mol/L, benefiting from its excellent noise equivalent power (∼7.1 × 10 −12 W). Its superior stability and standard semiconductor fabrication process indicate practical application potential and promising commercialization prospects of our spectrometer.