Detection of high-power two-mode squeezing by sum-frequency generation

TL;DR

This paper proposes using sum-frequency generation as a robust method to detect high-power two-mode squeezing, offering advantages over traditional homodyne detection in efficiency and bandwidth.

Contribution

It introduces a novel SFG-based detection scheme for high-power two-mode squeezed states, with a formalism that unifies different squeezing types and relates input squeezing to measured noise.

Findings

SFG detection is more robust to detection inefficiency.

SFG detection has a broader acceptance bandwidth.

The method effectively measures squeezing in high-power regimes.

Abstract

We introduce sum-frequency generation (SFG) as an effective physical two-photon detector for high power two-mode squeezed coherent states with arbitrary frequency separation, as produced by parametric oscillators well above the threshold. Using a formalism of "collective modes", we describe both two-mode squeezing and degenerate squeezing on equal footing and derive simple relations between the input degree of squeezing and the measured SFG quadrature noise. We compare the proposed SFG detection to standard homodyne measurement, and show advantages in robustness to detection inefficiency (loss of SFG photons) and acceptance bandwidth.