Amplitude Noise Suppression in Frequency-Doubled Lasers: A Lyapunov Mechanism for Intensity Stabilization in Coupled Oscillator Systems
Abstract
Multimode intracavity frequency-doubled lasers can reach states of amplitude noise suppression orders of magnitude beyond the predictions of independent-mode partition statistics. We show that the chi2 coupled-wave dynamics in the doubling crystal admit a Lyapunov functional whose monotone decrease under each crystal pass establishes a constant-intensity manifold as the per-pass descent target of the mode dynamics. We confirm the mechanism in an intracavity frequency-doubled Nd:YVO4-LBO laser, observing a 100 fold contrast between full and Fabry-Perot-filtered output noise at fixed detector bandwidth, well beyond the statistical-averaging baseline. The mechanism rests on the algebraic structure of the coupling, a coherent superposition of oscillators sharing a quadratic dissipative channel, and is therefore a candidate for analogous noise-suppression effects in other coupled oscillator systems with the same algebraic form.
Keywords
Cite
@article{arxiv.2605.13745,
title = {Amplitude Noise Suppression in Frequency-Doubled Lasers: A Lyapunov Mechanism for Intensity Stabilization in Coupled Oscillator Systems},
author = {Thomas M. Baer},
journal= {arXiv preprint arXiv:2605.13745},
year = {2026}
}
Comments
v2: corrected three reference errors in bibliography (refs [3], [9], [10]); removed two uncited references. No changes to body text, equations, or figures