Evaluation of Acoustic Waves in Acousto-Optical Devices by Ultrasonic Imaging.

Sergey A Titov,Alexander S Machikhin,Vitold Ed Pozhar

doi:10.3390/ma15051792

Abstract

The structure of the acoustic field defines the key parameters of acousto-optical (AO) devices. To confirm their compliance with the expected values in the presence of multiple real factors, AO crystalline cells require accurate experimental investigation of the acoustic field after being totally assembled. For this purpose, we propose to detect and quantify all the acoustic waves propagating in AO cells using an impulse acoustic microscopy technique. To validate this approach, we have analyzed both theoretically and experimentally the modes, amplitudes, propagation trajectories, and other features of the ultrasonic waves generated inside an AO modulator made of fused quartz. Good correspondence between theoretical and experimental data confirms the effectiveness of the proposed technique.

Highlights

The structure of induced acoustic fields defines the performance of AO devices to a large extent
We have shown that impulse acoustic microscopy is quite informative tool for quantitative characterization of the acoustic field in AO cells
It allows to define the modes, amplitudes, propagation trajectories and other features of the ultrasonic waves propagating in the crystal even after multiple reflections

Summary

Introduction

Acousto-optic (AO) interaction is a physical effect, which is used for modulation, deflection, and spectral and spatial filtration of electromagnetic radiation [1,2]. As they are compact, monolithic and free of moving components, AO devices are widespread in industrial, biomedical and scientific applications [3–5]. The physical principle of most AO instruments consists of Bragg diffraction of light by ultrasound in crystalline media. Precise theoretical consideration and modeling give a chance to predict and protect the characteristic degradation at the design stage, but the real structure of an acoustic field may only be revealed experimentally. It is essential to carefully examine each assembled AO cell and certify it in terms of the real acoustic field structure

Methods

Discussion

Conclusion