Continuous variable entanglement measurement without phase locking

TL;DR

This paper introduces a straightforward method for measuring continuous variable entanglement in bright EPR beams that eliminates the need for phase locking and local oscillators by using wave plates for phase shifts.

Contribution

It presents a novel entanglement measurement technique that simplifies the process by avoiding phase locking and local oscillators, utilizing wave plates instead.

Findings

Effective entanglement measurement without phase locking.

Utilizes wave plates for phase shifts in bright EPR beams.

Simplifies experimental setup for continuous variable entanglement.

Abstract

A new simple entanglement measurement method is proposed for the bright EPR beams generated from a non-degenerate optical parametric amplifier operating at deamplification. Due to the output signal and idler modes are frequency degenerate and in phase, the needed phase shift of interference for the measurement of the correlated phase quadratures and anti-correlated amplitude quadratures can be accomplished by a quarter-wave plate and a half wave plate without separating the signal and idler beam. Therefore, phase locking and local oscillators are avoided.