Two Color Entanglement

TL;DR

This paper demonstrates the generation of entangled light at two different wavelengths using a continuous variable approach with optical parametric oscillation, achieving measurable non-classical correlations.

Contribution

It reports the first generation of two-color entangled states in the continuous variable regime using a PPKTP-based OPO above threshold.

Findings

Achieved an inseparability of I=0.82 indicating strong entanglement.

Demonstrated non-classical quadrature correlations of about -0.86 dB.

Used filter cavities to effectively separate local oscillators from entangled sidebands.

Abstract

We report on the generation of entangled states of light between the wavelengths 810 and 1550 nm in the continuous variable regime. The fields were produced by type I optical parametric oscillation in a standing-wave cavity build around a periodically poled potassium titanyl phosphate crystal, operated above threshold. Balanced homodyne detection was used to detect the non-classical noise properties, while filter cavities provided the local oscillators by separating carrier fields from the entangled sidebands. We were able to obtain an inseparability of I=0.82, corresponding to about -0.86 dB of non-classical quadrature correlation.