Physical applications of photoacoustic spectroscopy

Abstract

PA [98]photoacoustic spectroscopy is applied ________ *)The basic principle of non-photoacoustic spectroscopies is that the heating of sample due to absorption of modulated light beam causes both temperature fluctuations and thermal expansion of sample.

The size effect in the AgOx-type super-resolution near-field structure

“…In our experiment, photoacoustic measurement has been used, because it is difficult to detect the absorption spectrum of AgO x -type Super-RENS using ordinary transmission or reflection methods due to its characters of high reflection and scattering. The photoacoustic spectroscopy is a direct monitor of energy band gap and the nonradiative relaxation channel, and can detect the spectra of any type of solids whether it is crystalline, powder or gel [14][15][16].…”

Photoacoustic Spectroscopy in the Optical Characterization of Foodstuff: A Review

“…Spectroscopy is the study of the interaction of electromagnetic radiation with atoms and molecules to provide qualitative and quantitative chemical and physical (structural) information, that is contained within the wavelength or frequency spectrum of energy that is either absorbed or emitted [30]. According to Sunandana [31]; Photoacoustic spectroscopy (PAS), the oldest form of photothermal techniques, is a type of spectroscopy and its name "photoacoustic" (PA) generally implies a particular technique or mechanism of detecting and measuring the optical absorption of opaque and diffuse materials, among others. e basic principle of photothermal spectroscopy is the detection of heat produced in a sample due to nonradiative de-excitation processes resulting from the absorption of intensity-modulated light (wave of pulsed light) by the sample.…”

High-sensitivity methane detection based on QEPAS and H-QEPAS technologies combined with a self-designed 8.7 kHz quartz tuning fork

“…In QEPAS method, after absorbing the specific wavelength of the laser, the target gas molecules will release heat to the surrounding environment through the non-radiative transition. Based on the photoacoustic effect [34] , the continuous emission of acoustic waves will occur at the position of contact between the laser and the gas molecules due to the periodic modulated light beam [35] , [36] , [37] , [38] , [39] . These acoustic waves will induce vibrations in the detector of quartz tuning fork (QTF) within QEPAS sensing system, thereby exploiting its piezoelectric effect to generate the piezoelectric signal on its surface that can be utilized for gas concentration inversion.…”