Quasicollinear AOTF spectral transmission under temperature gradients aroused by ultrasound power absotption

Quasicollinear geometry is a special configuration of acousto-optic (AO) diffraction that provides extremely large AO interaction length for achieving extremely high spectral resolution of AO tunable filters (AOTFs). Large AO interaction length also makes possible to implement multifrequency diffrac...

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Bibliographic Details
Published in:IEEE transactions on ultrasonics, ferroelectrics, and frequency control ferroelectrics, and frequency control, 2022, p.1-1
Main Authors: Mantsevich, Sergey N., Balakshy, Vladimir I., Yushkov, Konstantin B., Molchanov, Vladimir Ya, Tretiakov, Sergey A.
Format: Article
Language:English
Subjects:
Acoustics
acousto-optic tunable filter
Crystals
Diffraction
Optical diffraction
Optical filters
quasicollinear diffraction
temperature gradients
Temperature measurement
transmission function
Ultrasonic imaging
ultrasound attenuation
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Summary:Quasicollinear geometry is a special configuration of acousto-optic (AO) diffraction that provides extremely large AO interaction length for achieving extremely high spectral resolution of AO tunable filters (AOTFs). Large AO interaction length also makes possible to implement multifrequency diffraction in quasicollinear AOTFs that has found multiple applications in modern optoelectronics. The most widespread of them being ultrashort laser pulse shaping when the pulse shape and spectral composition is controlled by the spectral composition of the ultrasound pulse aroused in the AO crystal. The operation of quasicollinear AOTFs is accompanied by the appearance of the temperature gradients in the AO device mainly due to the acoustic power absorption by the material. We experimentally assessed the influence of these gradients on the AOTF spectral characteristics. A theoretical model based on the Raman-Nath equations was proposed that allows to consider the influence of ultrasound attenuation and temperature gradients on the AOTF transmission. This model is valid for transmission simulations both in single-frequency and modulated-frequency AOTF operation modes. The study includes effects of acoustic wave attenuation and AO phase matching shift caused by inhomogeneous crystal temperature along the optical beam path. The compensation strategy based on ultrasound frequency and magnitude adjustment is proposed for minimizing the effect of temperature gradients and acoustic field attenuation on AOTF spectral transmission for broadband operation in ultrashort laser pulse shaping.
ISSN:0885-3010
DOI:10.1109/TUFFC.2022.3218736