Highly Sensitive and Fast Hydrogen Detection Based on Light-Induced Thermoelastic Spectroscopy

As a new energy source, hydrogen (H 2 ) detection is a hot topic in recent years. Because of the weak absorption characteristic, laser spectroscopy-based H 2 detection is challenging. In this paper, a highly sensitive H 2 sensor based on light-induced thermoelastic spectroscopy (LITES) technique is demonstrated for the first time. A continuous-wave, distributed feedback diode laser with emission in the 2.1 μm region was adopted as the excitation source to target the strongest H 2 absorption line of 4,712.90 cm −1 . A Herriott multipass cell with an optical length of 10.1 m was chosen to further improve the H 2 absorption. With the feature of processing the raw input data without data preprocessing and…