Improved quantum correlations in second harmonic generation with a squeezed pump

TL;DR

This paper demonstrates that using a squeezed pump in second harmonic generation enhances quantum correlations and entanglement, with minimal impact on conversion efficiency at most pump intensities.

Contribution

It shows that a squeezed pump improves quantum entanglement and EPR paradox violations in second harmonic generation compared to a coherent pump.

Findings

Greater violations of harmonic entanglement criteria with squeezed pump

Enhanced EPR paradox violations in harmonic generation

Conversion efficiency remains stable except at very low pump intensities

Abstract

We investigate the effects of a squeezed pump on the quantum properties and conversion efficiency of the light produced in single-pass second harmonic generation. Using stochastic integration of the two-mode equations of motion in the positive-P representation, we find that larger violations of continuous-variable harmonic entanglement criteria are available for lesser effective interaction strengths than with a coherent pump. This enhancement of the quantum properties also applies to violations of the Reid-Drummond inequalities used to demonstrate a harmonic version of the Einstein-Podolsky-Rosen paradox. We find that the conversion efficiency is largely unchanged except for very low pump intensities and high levels of squeezing.