Study on contribution of the asymmetric stress to the birefringence induced by an ultrashort single laser pulse inside fused silica glass

Abstract

Stress induced birefringence due to asymmetry in axial and radial directions that is generated because of the interaction of ultrashort laser pulses with a transparent material is numerically studied. The coupled equations of nonlinear Schrodinger and plasma density evolution are solved to calculate the deposited energy density and initial temperature profile. Fourier's heat equation and the equations related to the thermo-elasto plastic model are solved to calculate the temperature evolution and distribution of induced displacement inside the material, respectively. Finally, by numerically calculating the distribution of the induced refractive index changes experienced by both axially and radially probe beams, induced stress birefringence is calculated for different characteristics of writing pulses. Furthermore, the induced stress birefringence is experimentally realized, and the effect of the energy of the writing pulse is investigated. To know how the induced refractive index changes and birefringence distributions depend on parameters of the writing pulse is crucial to obtain high performance guiding structures and polarization-sensitive as well as polarization-independent components.