Photoacoustic elastic bending in thin film–substrate system: Experimental determination of the thin film parameters

Todorović, D. M.; Rabasović, Mihailo D.; Markushev, D. D.; Sarajlić, Milija

doi:10.1063/1.4890346

Cited by 24 publications

(27 citation statements)

References 39 publications

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“…All plates were prepared from the same non-degenerated n-type Si wafer (3-5 Ω cm, ⟨100⟩ oriented) having the electron concentration of n 0 ¼ 9 Â 10 20 m À3 . 29 The samples thus obtained were excited with a laser diode emitting light at 656 nm with an intensity of I 0 = 10 W/m 2 and photon energy ε greater than the Si bandgap ε g . The absorption coefficient of our Si samples at the diode wavelength is β ¼ 2:58 Â 10 5 m À1 .…”

Section: Methodsmentioning

confidence: 99%

Experimental photoacoustic observation of the photogenerated excess carrier influence on the thermoelastic response of n-type silicon

Markushev

Aleksić

Pantić

et al. 2020

Journal of Applied Physics

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Based on the experimental and theoretical signals of an open photoacoustic cell operating with modulation frequencies from 20 Hz to 20 kHz, a significant contribution of photogenerated excess carriers on the thermal and thermoelastic responses of an n-type silicon plate is observed for the very first time. This is achieved by comparing the measured amplitude and phase of the photoacoustic signal with their corresponding theoretical thermoelastic counterparts, for high enough modulation frequencies mainly. It is shown that the amplitude of the thermoelastic component of plasma-thin samples varies about two orders of magnitude with respect to the corresponding one of plasma-thick samples. Furthermore, we find a maximal temperature difference ΔT = − 35 nK between the illuminated and non-illuminated sample surfaces, which shows that thin silicon plates with excess carriers could be used as heat sinks.

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Section: Methodsmentioning

confidence: 99%

Experimental photoacoustic observation of the photogenerated excess carrier influence on the thermoelastic response of n-type silicon

Markushev

Aleksić

Pantić

et al. 2020

Journal of Applied Physics

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“…The detection of the acoustic signal coming from a sample illuminated by the modulated radiation Perondi and Miranda, 1987;Vargas and Miranda, 1988) represents the basis of all open-cell photoacoustic (PA) measurements. The signal amplitude and phase changes are monitored in the modulation frequency domain of 20 Hz to 20 kHz (Rabasović et al, 2009;Todorović et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Electro-acustic influence of the measuring system on the photoacoustic signal amplitude and phase in frequency domain

Aleksić

Markushev

Rabasović

et al. 2016

Facta Univ Phys Chem Technol

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The paper discusses the most common impacts of the measuring system on the amplitude and phase of the photoacoustic signals in the frequency domain using the opencell experimental setup. The highest signal distortions are detected at the ends of the observed modulation frequency range from 20 Hz to 20 kHz. The attenuation of the signal is observed at lower frequencies, caused by the electronic filtering of the microphone and sound card, with characteristic frequencies of 15 Hz and 25 Hz. At higher frequencies, the dominant signal distortions are caused by the microphone acoustic filtering, having characteristic frequencies around 9 kHz and 15 kHz. It has been found that the microphone incoherent noise, the so called flicker noise, is negligibly small in comparison to the signal and does not affect the signal shape. However, a coherent noise originating from the power modulation system of the light source significantly affects the shape of the signal in the range greater than 10 kHz. The effects of the coherent noise and measuring system influence are eliminated completely using the relevant signal correction procedure targeting the photoacoustic signal generated by the sample.

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“…Resonant peaks observed in this part of frequency domain are, throughout literature, attributed to the influence of measurement chain, although, in measurements, they occur at frequencies lower than expected (frequency characteristic of the microphone, the amplifier, and other electronics) [27][28][29]. Minimum volume cell has already been observed as an electro-acoustic resonator and it has been modeled with cascade filter array, with transfer function represented as the combination of two Helmholtz resonators:…”

Section: Helmholtz Resonances-the Influence Of the Measurement Chainmentioning

confidence: 99%

Developing the Techniques for Solving the Inverse Problem in Photoacoustics

Nesic

Popović

Galović

2019

Atoms

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In this work, theoretically/mathematically simulated models are derived for the photoacoustic (PA) frequency response of both volume and surface optically-absorbing samples in a minimum volume PA cell. In the derivation process, the thermal memory influence of both the sample and the air of the gas column are accounted for, as well as the influence of the measurement chain. Within the analysis of the TMS model, the influence of optical, thermal, and elastic properties of the sample was investigated. This analysis revealed that some of the processes, characterized by certain sample properties, exert their dominance only in limited modulation frequency ranges, which are shown to be dependent upon the choice of the sample material and its thickness. Based on the described analysis, two methods are developed for TMS model parameter determination, i.e., sample properties which dominantly influence the PA response in the measurement range: a self-consistent procedure for solving the exponential problems of mathematical physics, and a well-trained three-layer perceptron with back propagation, based upon theory of neural networks. The results of the application of both inverse problem solving methods are compared and discussed. The first method is shown to have the advantage in the number of properties which are determined, while the second one is advantageous in gaining high accuracy in the determination of thermal diffusivity, explicitly. Finally, the execution of inverse PA problem is implemented on experimental measurements performed on macromolecule samples, the results are discussed, and the most important conclusions are derived and presented.

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Photoacoustic elastic bending in thin film–substrate system: Experimental determination of the thin film parameters

Cited by 24 publications

References 39 publications

Experimental photoacoustic observation of the photogenerated excess carrier influence on the thermoelastic response of n-type silicon

Experimental photoacoustic observation of the photogenerated excess carrier influence on the thermoelastic response of n-type silicon

Electro-acustic influence of the measuring system on the photoacoustic signal amplitude and phase in frequency domain

Developing the Techniques for Solving the Inverse Problem in Photoacoustics

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