Random quasi-phase-matched second-harmonic generation in periodically poled lithium tantalate

TL;DR

This paper demonstrates random quasi-phase-matched second-harmonic generation in periodically poled lithium tantalate, revealing broadband spectral response and stochastic domain effects, supported by experimental results and numerical modeling.

Contribution

It provides the first experimental observation and modeling of random quasi-phase-matching effects in lithium tantalate, highlighting stochastic domain influence on SHG.

Findings

Quadratic growth of harmonic output with fundamental power

Broadband spectral response observed

Pattern formation due to stochastic domain distribution

Abstract

We observe second harmonic generation via random quasi-phase-matching in a 2.0 \mu m periodically poled, 1-cm-long, z-cut lithium tantalate. Away from resonance, the harmonic output profiles exhibit a characteristic pattern stemming from a stochastic domain distribution and a quadratic growth with the fundamental excitation, as well as a broadband spectral response. The results are in good agreement with a simple model and numerical simulations in the undepleted regime, assuming an anisotropic spread of the random nonlinear component.