Harmonics-assisted optical phase amplification with a self-mixing thin-slice Nd:GdVO4 laser operating in the self-induced skew cosh Gaussian mode

TL;DR

This paper demonstrates harmonic-assisted phase amplification in a thin-slice Nd:GdVO4 laser using a self-mixing scheme, achieving significant phase gain through mode interference and skew cosh Gaussian mode oscillation.

Contribution

It introduces a novel self-induced skew cosh Gaussian mode in a thin-slice laser, enabling enhanced phase amplification via modal interference in a self-mixing setup.

Findings

Fifty-fold phase amplification achieved.

Modal interference increases modulation bandwidth.

Self-induced skew cosh Gaussian mode formation verified.

Abstract

Harmonic-assisted phase amplification was achieved in a 300-micrometer-thick Nd:GdVO4 laser in the self-mixing interference scheme. The key event is the self-induced skew cosh Gaussian (e.g., skew-chG) mode oscillation in a thin-slice solid-state laser with wide-aperture laser-diode pumping. The skew-chG mode was proved to be formed by the phase-locking of nearly frequency-degenerate TEM00 and annular fields. The resultant modal-interference-induced gain modulation at the beat frequency between the two modal fields, which is far above the relaxation oscillation frequency, increased experimental self-mixing modulation bandwidth accordingly. Fifty-fold phase amplification was achieved in a strong optical feedback regime.