Generating highly squeezed Hybrid Laguerre-Gauss modes in large-Fresnel-number Degenerate Optical Parametric Oscillators

TL;DR

This paper theoretically investigates a large-Fresnel-number degenerate optical parametric oscillator pumped by a Gaussian beam, revealing that hybrid Laguerre-Gauss modes can exhibit significant quantum squeezing, especially in modes not amplified above threshold.

Contribution

It introduces a theoretical framework for generating highly squeezed hybrid Laguerre-Gauss modes in large-Fresnel-number OPOs, focusing on quantum properties of non-amplified modes.

Findings

Hybrid Laguerre-Gauss modes can exhibit large quadrature squeezing.

Only lower OAM modes are amplified above threshold.

Quantum properties of non-amplified modes are characterized.

Abstract

We theoretically describe the quantum properties of a large Fresnel number degenerate optical parametric oscillator with spherical mirrors that is pumped by a Gaussian beam. The resonator is tuned so that the resonance frequency of a given transverse mode family coincides with the down-converted frequency. After demonstrating that only the lower orbital angular momentum (OAM) Laguerre-Gauss modes are amplified above threshold, we focus on the quantum properties of the rest of (classically empty) modes. We find that combinations of opposite OAM (Hybrid Laguerre-Gauss modes) can exhibit arbitrary large quadrature squeezing for the lower OAM non amplified modes.