High sensitive resonant infrared photo-acoustic gas sensitive system is studied

the resonant frequency spectrum of the system is measured and analyzed and a new resonant model is observed.After a series of comparison

it’s found that the system has better performance in sensitivity and SNR using new resonant model.It is believed that the new resonant model is caused by the resonance of the two buffer cavities on both sides.The influence of output cavity structure of microphone on the opto-acoustic signal

it is found that the signal can be amplified obviously by increasing the distance from microphone to resonant cavity.In addition

the signal can be amplified if a reflecting metal film is located in the outlet of laser.