Cantilever-enhanced photoacoustic spectroscopy for gas sensing: A comparison of different displacement detection methods

Photoacoustic spectroscopy (PAS) combines the advantages of high sensitivity, high specificity and zero background, which is very suitable for trace gas detection. Cantilever-enhanced photoacoustic spectroscopy (CEPAS) utilizes highly sensitive mechanical cantilevers to further enhance the photoacoustic signal and shows a gas concentration detection limit of parts per trillion. This review is intended to summarize the recent advancements in CEPAS based on different displacement detection methods, such as Michelson interference, Fabry-Perot interference, light intensity detection, capacitive, piezoelectric and piezoresistive detection. Fundamental mechanisms and technical requirements of CEPAS are also provided in the literature. Finally, potential challenges and further opportunities are also discussed.