A BRIEF OVERVIEW OF CAVITY-ENHANCED RAMAN SPECTROSCOPY FOR GAS DETECTION AND ANALYSIS

The gas sensor market is predominantly dominated by electrochemical, semiconductor, and non-dispersive infrared absorption (NDIR)-based optical sensors. While these technologies offer a broad range of detectable gases, identifying unknown gas mixtures remains a challenge, as sensor selection must be predetermined to minimize cross-talk. As an optical alternative, Raman spectroscopy provides a versatile solution, requiring no prior knowledge and covering nearly all gas compounds. However, its application is limited by a low quantum yield due to the weak scattering cross-section of gases. To address this limitation, various enhancement techniques have been explored, with cavity-enhanced Raman spectroscopy emerging as a promising approach. By utilizing optical cavities, this technique increases laser beam power and extends analyte interaction lengths, enabling improved detection while allowing for cost-effective instrumentation. This review examines the advancements in cavity-enhanced Raman spectroscopy, focusing on research trends, typical experimental setups, and the achieved spectral resolutions.