Twin-beam intensity-difference squeezing below 10 Hz

TL;DR

This paper demonstrates the generation of strong twin-beam intensity-difference squeezing below 10 Hz using a cavity-free four-wave mixing process in Rb vapor, enabling low-frequency quantum applications.

Contribution

It introduces a stable, cavity-free method for producing low-frequency twin-beam squeezing with noise reduction techniques, advancing quantum optics capabilities.

Findings

Achieved twin-beam squeezing below 10 Hz.

Used diode lasers and passive stability techniques.

Enabled potential low-frequency quantum imaging applications.

Abstract

We report the generation of strong, bright-beam intensity-difference squeezing down to measurement frequencies below 10 Hz. We generate two-mode squeezing in a four-wave mixing (4WM) process in Rb vapor, where the single-pass-gain nonlinear process does not require cavity locking and only relies on passive stability. We use diode laser technology and several techniques, including dual seeding, to remove the noise introduced by seeding the 4WM process as well as the background noise. Twin-beam intensity-difference squeezing down to frequencies limited only by the mechanical and atmospheric stability of the lab is achieved. These results should enable important low-frequency applications such as direct intensity-difference imaging with bright beams on integrating detectors.