Picosecond opto-acoustic interferometry and polarimetry in high-index GaAs

TL;DR

This paper demonstrates a method using picosecond opto-acoustic interferometry and polarimetry to generate and monitor strain pulses in GaAs, enhancing detection sensitivity and providing detailed insights into elasto-optical anisotropy.

Contribution

It introduces a combined interferometric and polarimetric technique for detailed analysis of strain pulses in GaAs with improved sensitivity.

Findings

Successful generation of quasi-longitudinal and quasi-transverse strain pulses.

Polarimetric detection enhances sensitivity and provides additional information.

Experimental results agree with theoretical analysis.

Abstract

By means of a metal opto-acoustic transducer we generate quasi-longitudinal and quasi-transverse picosecond strain pulses in a (311)-GaAs substrate and monitor their propagation by picosecond acoustic interferometry. By probing at the sample side opposite to the transducer the signals related to the compressive and shear strain pulses can be separated in time. In addition to conventional monitoring of the reflected probe light intensity we monitor also the polarization rotation of the optical probe beam. This polarimetric technique results in improved sensitivity of detection and provides comprehensive information about the elasto-optical anisotropy. The experimental observations are in a good agreement with a theoretical analysis.