Producing entangled photon pairs and quantum squeezed states in plasmas

TL;DR

This paper explores how plasmas can generate entangled photon pairs and quantum squeezed states via nonlinear four-wave mixing, with potential for high-rate quantum state production and noise suppression.

Contribution

It demonstrates the feasibility of producing entangled photons and squeezed states in plasma, highlighting methods to enhance interaction rates and suppress Raman scattering noise.

Findings

Polarization-entangled photon pairs can be generated in plasma.

Pump detuning affects the emission rate and noise characteristics.

Strong two-mode squeezed states can be produced with optimal detuning.

Abstract

Plasma is capable of mediating the conversion of two pump photons into two different photons through a relativistic four-wave mixing nonlinearity. Spontaneously created photon pairs are emitted at symmetric angles with respect to the colinear pump direction, and the emission rate is largest if they have identical frequency. Thus, two orthogonally polarized pumps can produce polarization-entangled photon pairs through a mm-long homogeneous plasma. The noise from Raman scattering can be avoided if the pump detuning differs from twice the plasma frequency. On the other hand, pump detuning exactly equal to twice the plasma frequency can significantly enhance the interaction rate, which allows for the production of strong two-mode squeezed states. Remarkably, the amplified noise from Raman scattering are correlated and hence can be suppressed in one of the output quadratures, thereby maintaining the squeezing magnitude.