Multicomponent Gas Measurement Method Based on Miniaturized and Scalable Multiresonator Photoacoustic Spectroscopy

This paper presents and demonstrates a multicomponent gas measurement method based on miniaturized and expandable multiresonator photoacoustic spectroscopy (MR-PAS). Existing multiresonant photoacoustic cells (MR-PAC) with parallel-placed H-type structures are large in size and difficult to expand the number of resonators due to the need for separate collimation. In this paper, a new type of MR-PAC with acoustic resonators uniformly distributed in the vertical section of the absorption cavity was designed based on T-type structure. The shared absorption cavity allows multiple laser beams to be combined and then collimated, while the buffer cavity is not required, which significantly reduces the volume. The circumferential distribution of the acoustic resonators solves the problem of expanding the number of detected gases. The cavity volume of the MR-PAC with four acoustic resonators designed in this paper was only 154.34 μL. The feasibility and performance of MR-PAC were verified by the simultaneous detection of CH₄, C₂H₂, C₂H₆, and C₂H₄. Within an integration time of 1000 s, the minimum detectable concentrations were as low as 86.1, 4.3, 188.1, and 127.9 ppb, respectively. The MR-PAC designed in this paper has the advantages of miniaturization and scalability, which has high potential for application in the field of multicomponent gas sensing.