Defect Detection Using Photoacoustic Effect of Semiconductor Laser and Propagation Characteristic of Photoacoustic Signal

The amplitude of the photoacoustic effect for an optical source moving at the sound speed in a one-dimensional geometry increases linearly in time without bound in the linear acoustic regime. Here, use of this principle is described for trace detection of gases, using two frequency-shifted beams from a CO2 laser directed at an angle to each other to give optical fringes that move at the sound speed in a cavity with a longitudinal resonance. The photoacoustic signal is detected with a high-Q, piezoelectric crystal with a resonance on the order of 443 kHz. The photoacoustic cell has a design analogous to a hemispherical laser resonator and can be adjusted to have a longitudinal resonance to match that of the detector crystal. The grating frequency, the length of the resonator, and the crystal must all have matched frequencies; thus, three resonances are used to advantage to produce sensitivity that extends to the parts-per-quadrillion level.

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Нелинейный фотоакустический отклик на механические напряжения вблизи отверстия в пластине из алюминиевого сплава Д16

Письма в журнал технической физики ◽

10.21883/pjtf.2020.04.49045.18100 ◽

2020 ◽

Vol 46 (4) ◽

pp. 22

Author(s):

А.Л. Глазов ◽

Н.Ф. Морозов ◽

К.Л. Муратиков

Keyword(s):

Aluminum Alloy ◽

Laser Radiation ◽

Thermal Effect ◽

Modulation Frequency ◽

Photoacoustic Signal ◽

Theoretical Description ◽

Mechanical Stresses ◽

Electronic Subsystem ◽

Sound Generation ◽

Photoacoustic Effect

The features of the behavior of the photoacoustic signal depending on mechanical stresses near the hole in the plate made of aluminum alloy D16 are investigated. A new nonlinear photoacoustic effect was discovered, which consists in the appearance of a nonlinear component of the photoacoustic signal depending on mechanical stresses near the hole. This dependence is recorded in the signal at the modulation frequency of the laser radiation. A theoretical description of the discovered effect of sound generation by the thermoelastic mechanism in stressed metals is proposed basing on the consideration of the thermal effect of laser radiation on their electronic subsystem.

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Step-Scan FT-IR Photoacoustic Spectroscopy: The Signal Phase

Applied Spectroscopy ◽

10.1366/0003702971940576 ◽

1997 ◽

Vol 51 (4) ◽

pp. 552-557 ◽

Cited By ~ 8

Author(s):

M. W. C. Wahls ◽

J. P. Toutenhoofd ◽

L. H. Leyte-Zuiderweg ◽

J. de Bleijser ◽

J. C. Leyte

Keyword(s):

Carbon Black ◽

Polymer Films ◽

Photoacoustic Spectroscopy ◽

Photoacoustic Signal ◽

New Method ◽

Signal Phase ◽

Photoacoustic Effect ◽

Ft Ir ◽

Phase Spectra ◽

Pet Films

The model of Rosencwaig and Gersho for the photoacoustic effect is tested. The use of carbon black samples as a phase reference to estimate the apparatus phase φapp from the experimental signal phase φexp turned out to be ambiguous. A new method is presented to correct the experimental signal phases φexp of polymer films for the apparatus phase φapp. The photoacoustic signal phase of some well-defined poly(ethyleneterephthalate) (PET) films is obtained. As a phase reference, transparent thermally thick polymer films were found to be more convenient and dependable than carbon black samples. The resulting phase spectra of thermally thick and thermally thin PET films confirm the Rosencwaig–Gersho theory.

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Iterative method for determination of the laser beam profile and τV-T

Facta universitatis - series Physics Chemistry and Technology ◽

10.2298/fupct0801071r ◽

2008 ◽

Vol 6 (1) ◽

pp. 71-76

Author(s):

Mihailo Rabasovic ◽

Dragan Markushev

Keyword(s):

Relaxation Time ◽

Laser Beam ◽

Photoacoustic Signal ◽

Linear Process ◽

Beam Profile ◽

Photoacoustic Tomography ◽

Spatial Profile ◽

Photoacoustic Effect ◽

Laser Beam Profile

Measuring the vibrational-to-translational relaxation time ?V-T in gases is one of the first applications of the photoacoustic effect. The spatial profile of the laser beam is crucial in these measurements because the multiphoton excitation is investigated. The multiphoton absorption is a non-linear process. Because of this, the top hat profile is preferable. It allows one to deal with nonlinearity in a simple manner. In order to reveal the real laser beam profile, we have slightly changed the theoretical profiles in such a manner that the best matching is obtained between theoretical and experimental photoacoustic signals. Still, there was a question: Is it possible to deduce the laser beam profile directly from the photoacoustic signal, thus avoiding manual changing of the laser beam profile? According to this paper, it is possible. The appropriate method has been found in another photoacoustics application: photoacoustic tomography. Thus, the method for the simultaneous determination of the spatial profile of the laser beam and vibrational-to-translational relaxation time is presented in this paper. It employs pulsed photoacoustics and an algorithm developed for photoacoustic tomography.

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EXPERIMENTAL CHARACTERIZATION OF A PHOTO-ACOUSTIC MEASUREMENT SYSTEM

Facta Universitatis, Series: Working and Living Environmental Protection ◽

10.22190/fuwlep1701053t ◽

2017 ◽

pp. 053 ◽

Cited By ~ 1

Author(s):

Slobodan Todosijević ◽

Dejan Ćirić ◽

Branko Radičević ◽

Zlatan Šoškić

Keyword(s):

Transfer Function ◽

Measurement System ◽

Photoacoustic Signal ◽

Electronic System ◽

Photoacoustic Effect ◽

Properties Of Materials ◽

Optical Properties Of Materials ◽

Non Destructive

The photoacoustic effect, as a non-destructive method, has increased application in defining thermal and optical properties of materials. Since the measurement of photoacoustic signal requires use of an electronic system, knowledge of the transfer function of the measurement system is a prerequisite for its application. This paper presents two different experimental techniques for the determination of the transfer function of a PA measurement system.

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Efficient combination of multiple high power semiconductor laser sources for photoacoustic signal generation in biomedical phantoms

10.1117/12.663910 ◽

2006 ◽

Cited By ~ 3

Author(s):

Vincent Cunningham ◽

Horacio Lamela

Keyword(s):

Semiconductor Laser ◽

High Power ◽

Photoacoustic Signal ◽

Signal Generation ◽

Power Semiconductor ◽

Laser Sources

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STUDY OF LASER ABLATION IN LIQUIDS USING PULSED PHOTOACOUSTIC TECHNIQUE

Modern Physics Letters B ◽

10.1142/s021798499600119x ◽

1996 ◽

Vol 10 (21) ◽

pp. 1053-1057

Author(s):

S.S. HARILAL ◽

RIJU C. ISSAC ◽

C.V. BINDHU ◽

V.P.N. NAMPOORI ◽

C.P.G. VALLABHAN

Keyword(s):

Laser Ablation ◽

Laser Energy ◽

Carbon Disulphide ◽

Signal Amplitude ◽

Photoacoustic Signal ◽

Photoacoustic Technique ◽

Photoacoustic Effect ◽

Liquid Benzene ◽

Benzene Toluene ◽

532 Nm

Laser ablation processes in liquid benzene, toluene and carbon disulphide have been investigated by pulsed photoacoustic technique using 532 nm radiation from a frequency doubled Q-switched Nd:YAG laser. The nature of variation of photoacoustic signal amplitude with laser energy clearly indicates that different phenomena are involved in the generation of photoacoustic effect and these are discussed in detail. Our results suggest multiphoton induced photofragmentation as the most plausible interaction process occurring during laser ablation in these liquids.

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Metal Surface Defect Detection System Based on Semiconductor Laser and Infrared Thermal Imaging

2019 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) ◽

10.1109/i2mtc.2019.8826839 ◽

2019 ◽

Author(s):

Zhijie Zhang ◽

Ningchen Dong ◽

Chenyang Zhao ◽

Wuliang Yin

Keyword(s):

Semiconductor Laser ◽

Metal Surface ◽

Defect Detection ◽

Thermal Imaging ◽

Surface Defect ◽

Detection System ◽

Infrared Thermal Imaging ◽

Surface Defect Detection

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Theoretical and experimental investigation of the photoacoustic effect in solids with residual stresses

Open Physics ◽

10.2478/bf02475859 ◽

2003 ◽

Vol 1 (3) ◽

Cited By ~ 4

Author(s):

K. Muratikov ◽

A. Glazov

Keyword(s):

Residual Stress ◽

Radial Crack ◽

Photoacoustic Signal ◽

External Loading ◽

Shear Stresses ◽

Thermoelastic Effect ◽

Simultaneous Application ◽

Photoacoustic Effect ◽

Thermoelastic Effects ◽

Crack Tips

AbstractModern experiment and theory in the field of residual stress detection by the photoacoustic method are summarized and analyzed. A multimode approach based on the simultaneous application of several photothermal and photoacoustic methods is proposed for the study of thermal and thermoelastic effects in solids with residual stress. Some experimental results obtained within the framework of this approach for Vickers indentation zones in ceramics are presented. The effect of annealing on the photoacoustic, piezoelectric signal for ceramics and the influence of the given external loading on the behavior of the photoacoustic signal near the radial crack tips is investigated. It is experimentally shown that both compressive and shear stresses contribute to the photoacoustic signal near the radial crack tips. The model of the photoacoustic, thermoelastic effect in solids with residual stress is proposed. It is based on the modified Murnaghan model of non-linear elastic bodies, which takes into account a possible dependence of the thermoelastic constant on stress. This model is further developed to explain the photoacoustic signal behavior near the radial crack tips. It is demonstrated that this model of the photoacoustic effect agrees qualitatively with the available experimental data.

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Photoacoustic Resonant Cell Remodified from Helmholtz Cavity for Multi-Gas Sensing Using Infrared Lasers

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.562-565.1016 ◽

2013 ◽

Vol 562-565 ◽

pp. 1016-1020

Author(s):

Jun Juan Zhao ◽

Xian Hui Li ◽

Zhan Zhao ◽

Xiao Ling Gai ◽

Yan Qi Liu

Keyword(s):

Gas Sensing ◽

Optical Power ◽

Photoacoustic Signal ◽

Infrared Lasers ◽

High Adsorption ◽

Photoacoustic Effect ◽

Experiment System ◽

Real Time Measurement ◽

On Line ◽

And Performance

This paper presents method and performance of the photoacoustic resonant cell remodified from Helmholtz cavity that can be used to detect photoacoustic signal of multi-gas. This technique has its physical basis in a phenomenon called the photoacoustic effect. The experiment system is composed of a resonant Helmholtz cavity, a sensitive microphone and two infrared lasers with high adsorption capability and specificity to the analyte. In our experiments, the average optical power at the laser operating point is 200mW for the 972nm laser (H2O detection) and 800mW for the10.653um laser (CO2detection), which are modulated at two different frequencies f1=175Hz and f2=125Hz. The remodified Helmholtz resonant on-line and real time measurement of the water vapour (300ppm) and carbodioxide (300ppm) conducted at their respective resonant frequency shown large signals about 4.41mV and 19.77mV respectively. The result demonstrated this cell used to test multi-gas is also feasible.

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