Significantly enhanced second order nonlinearity in domain walls of ferroelectrics

TL;DR

This paper reports a significant enhancement of second order nonlinearity in ferroelectric domain walls, enabling novel nonlinear optical phenomena and impacting existing optical techniques like quasi-phase-matching and electro-optic filtering.

Contribution

It introduces a new giant nonlinearity in ferroelectric domain walls caused by local symmetry breaking, leading to unique second harmonic beam patterns without reciprocal vectors.

Findings

Generation of hexagonally, conically, and trigonally distributed second harmonic beams

Enhanced second order nonlinearity impacts quasi-phase-matching techniques

Implications for electro-optic Solc filter designs

Abstract

Significantly enhanced second order nonlinearity resulting from local symmetry breaking in domain walls is reported. By this new giant nonlinearity, novel hexagonally, conically and trigonally distributed second harmonic beams closely related to domain wall patterns are generated without contribution of reciprocal vectors. Experimental results show that such nonlinearities have made important impact on quasi-phase-matching technique and electro-optic Solc filter, which needs careful reconsiderations.