Azimuthal entanglement and multichannel Schmidt-type decomposition of non-collinear biphotons

TL;DR

This paper analyzes the high degree of azimuthal entanglement in noncollinear biphoton states and proposes a scheme for its partial realization using a multichannel Schmidt-type decomposition.

Contribution

It introduces a detailed analysis of azimuthal entanglement and proposes a novel scheme for its partial realization in biphoton states.

Findings

High azimuthal entanglement with Schmidt parameter proportional to pump waist/wavelength

Proposed multichannel Schmidt-type decomposition scheme

Potential for enhanced quantum information applications

Abstract

Purely azimuthal entanglement is analyzed for noncollinear frequency-degenerate biphoton states. The degree of azimuthal entanglement is found to be very high, with the Schmidt parameter $K$ on the order of the ratio of the pump waist to its wavelength. A scheme is suggested for partial realization of this high entanglement resource in the form of a multichannel Schmidt-type decomposition.