Multicomponent gas Raman spectroscopy detection based on CERS–SERS technology

Abstract Real-time monitoring and analysis of multicomponent gases have shown great application prospects in environmental monitoring and industrial production control. This study introduces a gas detection system that integrates cavity-enhanced Raman spectroscopy (CERS) with surface-enhanced Raman spectroscopy (SERS), utilizing a Herriott multipass cell cavity. This design aims to address the challenge of weak Raman scattering signals commonly encountered in conventional Raman spectroscopy. Improving the Herriott optical multipass cell caused the laser to undergo multiple reflections inside the cavity, thereby increasing the optical path of the excitation light and the multicomponent gas. To further improve the detection sensitivity of the system to multicomponent gases, CERS was combined with SERS by depositing gold nanoparticles on the incident window. The experimental results showed that a maximum optical path of 6.09 m could be obtained by using two Herriott multipass cells with a 100-mm focal length and a 25.4-diameter (lens spacing: 210 mm; incident angle: 1.77°). The system achieved detection limits for CO 2 , H 2 , N 2 , and CH 4 at 57, 53, 82 and 66 ppm (3 σ ), respectively. This marked advancement enhances the capability of Raman spectroscopy to detect multicomponent gases.