We generate spatially multimode twin beams using 4-wave mixing in a hot atomic vapor in a phase-insensitive traveling-wave amplifier configuration. The far-field coherence area measured at 3.5 MHz is shown to be much smaller than the angular bandwidth of the process and bright twin images with independently quantum-correlated sub-areas can be generated with little distortion. The available transverse degrees of freedom form a high-dimensional Hilbert space which we use to produce quantum-correlated twin beams with finite orbital angular momentum.
@article{arxiv.0711.3439,
title = {Generation of spatially broadband twin beams for quantum imaging},
author = {V. Boyer and A. M. Marino and P. D. Lett},
journal= {arXiv preprint arXiv:0711.3439},
year = {2009}
}