China Instrument Network Instrument R&D Recently, Liu Xiao, an associate researcher at the Institute of Optics and Fine Mechanics Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, has made a breakthrough in multi-channel photoacoustic spectroscopy.
Simultaneous measurement of H2O, CH4 and CO2 by multi-channel photoacoustic spectroscopy
The related research work was published in Sensors and Actuators B: Chemical under the title Multi-resonator photoacoustic spectroscopy.
Photoacoustic spectroscopy is a kind of spectral sensing method with high sensitivity, good selectivity and simple structure. The multi-component synchronous detection sensor can be widely used in the fields of atmospheric detection, environmental monitoring, industrial and electric power, and an acoustic cavity of a photoacoustic spectrometer. There is only one optimal operating frequency f0. When multi-source simultaneous detection of multiple components is used, the corresponding photo-acoustic signals of each light source cannot be distinguished and extracted. Only time-division multiplexing or a laser frequency corresponding to a photoacoustic cell can be used. The method greatly increases the complexity, volume and cost of the photoacoustic spectroscopy multi-component detection system. Therefore, how to use a multi-light source for multi-component simultaneous detection of photoacoustic spectroscopy instruments has always been a technical bottleneck to be solved.
Gao Xiaoming's team has long been dedicated to photoacoustic spectroscopy and applied research. In recent years, he has made a series of innovative research results in photoacoustic spectroscopy. Recently, for the first time, Liu Ye has implemented a new multi-channel photoacoustic spectroscopy technology for detecting three resonant cavities simultaneously with a single detector. In this new photoacoustic spectroscopy technology, three acoustic resonances with different resonant frequencies are provided in a single photoacoustic cell. The cavity, so that the photoacoustic signals of the acoustic resonators do not interfere with each other, and the signal in each acoustic resonator can be detected synchronously with only one microphone. The feasibility of this new multi-channel photoacoustic spectroscopy technique has been validated by the simultaneous measurement of water vapor (H2O), carbon dioxide (CO2) and methane (CH4). Experimental studies have shown that there are no signals between the 3 resonant cavities in the photoacoustic cell The situation of mutual interference occurs, and the minimum detectable coefficient reaches 10-9cm-1W/Hz1/2, which is basically consistent with the performance of traditional photoacoustic spectroscopy instruments.
The new multi-channel photoacoustic spectroscopy technology will greatly expand the detection capabilities and application fields of the multi-components of the photoacoustic spectrum, and will in particular greatly facilitate and simplify the photoacoustic spectroscopy system for the detection of multi-wavelength aerosol absorption coefficients.
The research work was supported by the National Natural Science Foundation of China, the Youth Fund, and the Youth Innovation Promotion Association of the Chinese Academy of Sciences.
(Original Title: Hefei Research Institute has made new breakthroughs in multichannel photoacoustic spectroscopy)