PHASE OPTIMIZATION FOR QUANTITATIVE-ANALYSIS USING PHASE FOURIER-TRANSFORM PHOTOACOUSTIC-SPECTROSCOPY

Citation
H. Marchand et al., PHASE OPTIMIZATION FOR QUANTITATIVE-ANALYSIS USING PHASE FOURIER-TRANSFORM PHOTOACOUSTIC-SPECTROSCOPY, Optical engineering, 36(2), 1997, pp. 312-320
Citations number
22
Categorie Soggetti
Optics
Journal title
ISSN journal
00913286
Volume
36
Issue
2
Year of publication
1997
Pages
312 - 320
Database
ISI
SICI code
0091-3286(1997)36:2<312:POFQUP>2.0.ZU;2-4
Abstract
The phase of the photoacoustic signal is of prime importance for obtai ning accurate optical absorption coefficients using the photoacoustic technique, Variations in the spectrometer or the photoacoustic cell pa rameters between the measurement of the sample spectrum and the carbon black reference spectrum are the main source of phase shifts, We reco nsider a simple model that provides an accurate description of the pho toacoustic effect-including photoacoustic saturation thermally thick, homogeneous samples. The model includes absorption from a thin layer a t the sample surface. We propose a method for optimizing the photoacou stic phase for this model. The method is based on the internal calibra tion at the onset of the photoacoustic saturation, and on a simple ana lysis of the shape of the calculated surface absorption spectrum. Opti mization is illustrated with a simulated spectrum and an experimental spectrum of ethylene-propylene-rubber. (C) 1997 Society of Photo-Optic al Instrumentation Engineers.