Hydrogen, a promising fuel, has extensive applications in many sectors. However, its safe and widespread use necessitates reliable sensing methods. While tunable diode laser absorption spectroscopy (TDLAS) has proved to be an effective gas sensing method, detecting hydrogen using TDLAS is difficult due to its weak light absorption property in the infrared region. Addressing this issue, researchers developed an innovative calibration-free technique that significantly enhances the accuracy and detection limits for sensing hydrogen using TDLAS.