# A novel two-mode squeezed light based on double-pump phase-matching

## TL;DR

This paper introduces a new method for generating two-mode squeezed light using a double-pump four-wave mixing process, enabling wider bandwidths suitable for quantum memory applications.

## Contribution

It demonstrates a novel two-pump four-wave mixing scheme for producing two-mode squeezed light with adjustable refractive index and bandwidth, advancing quantum memory technology.

## Key findings

- Achieved frequency-degenerate two-mode squeezed light with separated spatial patterns.
- Demonstrated control of the probe's refractive index via angle adjustment.
- Produced wide-bandwidth squeezed light suitable for quantum memory.

## Abstract

A novel two-mode non-degenerate squeezed light is generated based on a four-wave mixing (4WM) process driven by two pump fields crossing at a small angle. By exchanging the roles of the pump beams and the probe and conjugate beams, we have demonstrated the frequency-degenerate two-mode squeezed light with separated spatial patterns. Different from a 4WM process driven by one pump field, the refractive index of the corresponding probe field $n_{p}$ can be converted to a value that is greater than $1$ or less than $1$ by an angle adjustment. In the new region with $n_{p}<1$, the bandwidth of the gain is relatively large due to the slow change in the refractive index with the two-photon detuning. As the bandwidth is important for the practical application of a quantum memory, the wide-bandwidth intensity-squeezed light fields provide new prospects for quantum memories.