Rotation of the noise ellipse for squeezed vacuum light generated via four-wave-mixing

TL;DR

This paper demonstrates the generation of a frequency-dependent rotated noise ellipse in a squeezed vacuum state produced by four-wave mixing in rubidium vapor, with theoretical modeling to optimize squeezing for interferometry.

Contribution

It introduces a method to control the rotation of the noise ellipse in squeezed vacuum light generated via four-wave mixing, supported by a theoretical model for optimization.

Findings

Noise ellipse rotation varies with detection frequency and experimental parameters

Theoretical model accurately describes the rotation effect

Potential application in frequency-dependent squeezing for interferometry

Abstract

We report the generation of a squeezed vacuum state of light whose noise ellipse rotates as a function of the detection frequency. The squeezed state is generated via a four-wave mixing process in a vapor of 85Rb. We observe that rotation varies with experimental parameters such as pump power and laser detunings. We use a theoretical model based on the Heisenberg-Langevin formalism to describe this effect. Our model can be used to investigate the parameter space and to tailor the ellipse rotation in order to obtain an optimum squeezing angle, for example, for coupling to an interferometer whose optimal noise quadrature varies with frequency.