All-Optical Cantilever-Enhanced Photoacoustic Spectroscopy in the Open Environment

Multi-mechanism collaboration enhanced photoacoustic analyzer for trace H2S detection

“…According to the sound wave enhancement characteristics of the resonance tube, it is of great significance to design an acoustic sensor with high detection sensitivity at the AR frequency of the PAC. A cantilever diaphragm is a rectangular narrow-band acoustic MR enhancement element with one end clamped and the other end free to vibrate [32] , [33] . Compared with the traditional circular acoustic-sensitive diaphragm, the oscillatory of the cantilever is almost not inhibited by the surface tensile stress [34] .…”

Direct Absorption and Photoacoustic Spectroscopy for Gas Sensing and Analysis: A Critical Review

“…Erbium‐doped ring lasers, [ 139 ] DFB, [ 140,141 ] $${\rm{C}}{{\rm{O}}_2}$$ lasers, [ 142 ] visible LEDs, [ 143 ] IR LEDs, [ 144 ] and THz diodes [ 145,146 ] are among the sources used with PA cells equipped with cantilevers. Lasers are more common than LEDs due to their higher optical power.…”

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

“…Michelson interferometer has high sensitivity and good stability, but the bulky volume and high cost limit its application in some specific fields. CEPAS based on Fabry-Perot interferometer is relatively compact [50] , [51] , [52] , [53] , [54] , [55] , [56] , [57] , [58] , [59] , [60] , [61] , [62] . A Fabry-Perot cavity is formed between the end facet of the fiber and the free end of the cantilever.…”

“…The length of the Fabry-Perot cavity varies along with the vibration of the cantilever, which can be calculated according to its output light intensity or phase detected by a demodulation unit, and then the displacement of cantilever can be obtained. In 2013, Wei et al firstly combined CEPAS with a Fabry-Perot interferometer [50] . A MEMS cantilever was fabricated by surface micro-machining technology and the interference signal was detected by a photodiode.…”