Integrated Backward Second-Harmonic Generation Through Optically Induced Quasi-Phase Matching

TL;DR

This paper demonstrates a novel integrated method for backward second-harmonic generation using optically induced quasi-phase matching, avoiding complex fabrication by employing seeded all-optical poling to create self-organized gratings.

Contribution

It introduces the first implementation of integrated first-order quasi-phase-matched BSHG via seeded all-optical poling, bypassing traditional fabrication challenges.

Findings

Self-organized gratings enable efficient BSHG.

Grating period significantly affects conversion efficiency.

Comparison of backward and forward processes reveals unique properties.

Abstract

Quasi-phase-matching for efficient backward second-harmonic generation (BSHG) requires sub-$\rm\mu$m poling periods, a non-trivial fabrication feat. For the first time, we report integrated first-order quasi-phase-matched BSHG enabled by seeded all-optical poling. The self-organized grating inscription circumvents all fabrication challenges. We compare backward and forward processes and explain how grating period influences the conversion efficiency. These results showcase unique properties of the coherent photogalvanic effect and how it can bring new nonlinear functionalities to integrated photonics.