A novel approach to reduce the influence of external conditions on the laser Doppler vibrometer signal acting in the nanometer range

Yarovoi, Leonid K.; Stepakhno, I. V.

doi:10.1088/1742-6596/1149/1/012023

Cited by 1 publication

(1 citation statement)

References 4 publications

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“…Запропонований підхідце (трихвильова) гетеродинна інтерферометрія (ТГІ) [10], що базується на багатохвилевому фотозмішуванні MWI (multy waves interference) [11]. Метод ТГІ розроблено для критичного збільшення чутливості до малих амплітуд коливань лазерних допплерівських віброметрів (ЛДВ) [12] та підвищення їх завадозахищеності [13]. В інтерференційних рефрактометрах так само, як і в ЛДВ, досліджуваним параметром є фаза оптичного випромінювання.…”

Section: засади застосування методу вимірювання фази лазерного променюunclassified

Application of Three-Wave Heterodine Interferometry for Nanorized Layers Thickness Measurement in the Process of Their Deposition

Lendiel¹,

Stepakhno²,

Yarovoi³

2022

Bull. Kyiv Polytech. Inst. Ser. Instrum. Mak.

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The paper proposes a new method of current measurement of the layer thickness of optical films in the process of their forming, in particular, by the method of vacuum deposition. Such films, among other things, are used to create a variety of optoelectronic devices and optical nanosensors for laboratory research in the chemical and pharmaceutical industries, for environmental monitoring. We propose a method for measuring the phase of a laser beam, which is based on heterodyne interferometry. The method of heterodyne interferometry in comparison with ordinary interference methods provides better S/N ration results due to the transfer of the investigated signal from the low frequency domain to heterodyne frequency. Our proposed approach is the three-wave heterodyne interferometry (TGI), otherwise - TWI (three waves interference). The TGI method is designed to critically increase the sensitivity to small amplitudes of laser Doppler vibrometers and increase their noise resistance. In interference gauges of optical film thickness, in refractometers, and in many other film thickness gauges as well as in laser Doppler vibrometers the investigated parameter is the phase shift of probing optical radiation. Therefore, the developments of TGI in laser Doppler vibrometers can be used to measure the phase shift. The analysis of the new method on mathematical model of TGI was provided. We have got the relations of the output signal of a three-wave heterodyne interferometer dependence on the phase shift , as well as on the thickness of optical films and on their refractive index. The simulation results show that for the optoelectronic equipment that provides with an error of up to 10 %, the absolute error of phase shift measurement, compared to the classical heterodyne interferometer, can be reduced to 103 times. The same results applies to the thickness of the optical coating layer. The paper also analyzes the results of experiments on the use of TGI in laser vibrometers and shows that they indicate the possibility of measuring the phase of optical radiation up to 10-5. The disadvantage of the proposed method is its non-linearity and, as a result, a limited linear range. Ways of extending the linear range are discussed.

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Section: засади застосування методу вимірювання фази лазерного променюunclassified

Application of Three-Wave Heterodine Interferometry for Nanorized Layers Thickness Measurement in the Process of Their Deposition

Lendiel¹,

Stepakhno²,

Yarovoi³

2022

Bull. Kyiv Polytech. Inst. Ser. Instrum. Mak.

View full text Add to dashboard Cite

show abstract

A novel approach to reduce the influence of external conditions on the laser Doppler vibrometer signal acting in the nanometer range

Cited by 1 publication

References 4 publications

Application of Three-Wave Heterodine Interferometry for Nanorized Layers Thickness Measurement in the Process of Their Deposition

Application of Three-Wave Heterodine Interferometry for Nanorized Layers Thickness Measurement in the Process of Their Deposition

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