Towards correcting atmospheric beam wander via pump beam control in a down conversion process

TL;DR

This paper explores using pump beam control in SPDC to correct atmospheric beam wander, aiming to improve free-space quantum communication by leveraging correlations between pump and photon modes.

Contribution

It demonstrates an experimental method to mitigate atmospheric beam wander by exploiting the correlation between pump and output photon modes in SPDC.

Findings

Beam deflection observed with SPAD-array.

Correlation-based correction potential shown.

Improved stability for quantum links suggested.

Abstract

Correlated photon pairs produced by a spontaneous parametric down conversion (SPDC) process can be used for secure quantum communication over long distances including free space transmission over a link through turbulent atmosphere. We experimentally investigate the possibility to utilize the intrinsic strong correlation between the pump and output photon spatial modes to mitigate the negative targeting effects of atmospheric beam wander. Our approach is based on a demonstration observing the deflection of the beam on a spatially resolved array of single photon avalanche diodes (SPAD-array).