Perturbation to optical polarization by laser-induced ultrasonic waves and its use for semiconductor characterization

Abstract

A pump-probe ultrasonic laser approach is developed for characterizing the anisotropic photoelasticity (AP) which is related to crystal structures of monocrystalline semiconductors (MSs). The approach exploits the perturbation to the polarization of the monochromatic laser beam when the laser beam interacts with the lattice of MSs. The actively generated strains at the microscopic scale (with a magnitude from 10-4 to 10-5) facilitates detailed, quantitative characterization of lattice properties MSs. A multiphysics model is established to interpret experimental observations, affirming there exists distinct orientation-dependence and crystal-structure-related symmetry of the perturbed polarization state, which is related to mechanical, photoelastic and strain-induced optical anisotropies of MSs.