Random laser action with coherent feedback via second-harmonic generation

TL;DR

This paper demonstrates a novel random laser with coherent feedback via second-harmonic generation, enabling broader wavelength response and potential applications in tunable and phase-matching-free nonlinear optics.

Contribution

It introduces the first experimental realization of random laser action with SHG-based coherent feedback, expanding the functionalities of random lasers beyond photoluminescence limitations.

Findings

Successful experimental demonstration of SHG-based random laser

Broader response waveband due to nonlinear frequency conversion

Potential for phase-matching-free nonlinear optical applications

Abstract

The random laser action with coherent feedback by second-harmonic generation (SHG) was experimentally demonstrated in this paper. Compared with the conventional random laser action based on photoluminescence effect, which needs strong photoresponse in the active medium and has a fixed response waveband due to the inherent energy level structure of the material, this random SHG laser action indicates a possible confinement of the nonlinear signal with ring cavities and widens the response waveband due to the flexible frequency conversion in nonlinear process. The combination of coherent random laser and nonlinear optics will provide us another possible way to break phase-matching limitations, with fiber or feedback-based wavefront shaping method to transmit the emission signal directionally. This work suggests potential applications in band-tunable random laser, phase-matching-free nonlinear optics and even brings in new consideration about random nonlinear optics (RNO).