Optical second harmonic generation in Yttrium Aluminum Borate single crystals (theoretical simulation and experiment)

TL;DR

This paper combines experimental measurements and first-principles calculations to analyze the second harmonic generation in Yttrium Aluminum Borate single crystals, revealing anisotropic susceptibilities and electron-phonon interaction effects.

Contribution

It provides the first combined experimental and theoretical analysis of second harmonic generation in YAB crystals, highlighting anisotropy and electron-phonon contributions.

Findings

Large anisotropy in optical susceptibilities observed.

Good agreement between calculations and experiments.

Opposite signs in inter-band and intra-band contributions.

Abstract

Experimental measurements of the second order susceptibilities for the second harmonic generation are reported for YAl3(BO3)4 (YAB) single crystals for the two principal tensor components xyz and yyy. First principles calculation of the linear and nonlinear optical susceptibilities for Yttrium Aluminum Borate YAl3(BO3)4 (YAB) crystal have been carried out within a framework of the full-potential linear augmented plane wave (FP-LAPW) method. Our calculations show a large anisotropy of the linear and nonlinear optical susceptibilities. The observed dependences of the second order susceptibilities for the static frequency limit and for the frequency may be a consequence of different contribution of electron-phonon interactions. The imaginary parts of the second order SHG susceptibility chi_{123}^{(2)}(omega), chi_{112}^{(2)}(omega), chi_{222}^{(2)}(omega), and chi_{213}^{(2)}(omega) are evaluated. We find that the 2(omega) inter-band and intra-band contributions to the real and imaginary parts of chi_{ijk}^{(2)}\l(omega) show opposite signs. The calculated second order susceptibilities are in reasonably good agreement with the experimental measurements.