Non-critically squeezed light via spontaneous rotational symmetry breaking

TL;DR

This paper demonstrates theoretically that a type I degenerate optical parametric oscillator can produce perfectly squeezed vacuum light with a Hermite-Gauss mode shape through spontaneous rotational symmetry breaking, regardless of pump level.

Contribution

It introduces a non-critical method for generating perfectly squeezed light via symmetry breaking in a spherical-mirror DOPO with Laguerre-Gauss modes.

Findings

Produces perfect squeezing at any pump level above threshold.

Symmetry imperfections have minimal impact on squeezing quality.

Squeezed light takes the form of a Hermite-Gauss mode.

Abstract

We theoretically address squeezed light generation through the spontaneous breaking of the rotational invariance occuring in a type I degenerate optical parametric oscillator (DOPO) pumped above threshold. We show that a DOPO with spherical mirrors, in which the signal and idler fields correspond to first order Laguerre-Gauss modes, produces a perfectly squeezed vacuum with the shape of a Hermite-Gauss mode, within the linearized theory. This occurs at any pumping level above threshold, hence the phenomenon is non-critical. Imperfections of the rotational symmetry, due e.g. to cavity anisotropy, are shown to have a small impact, hence the result is not singular.