We suggest and demonstrate a scheme to compensate spatial and spectral decoherence effects in the generation of polarization entangled states by type-I parametric downconversion. In our device a programmable spatial light modulator imposes a polarization dependent phase-shift on different spatial sections of the overall downconversion output and this effect is exploited to realize an effective purification technique for polarization entanglement.
@article{arxiv.1007.0505,
title = {Programmable purification of type-I polarization-entanglement},
author = {Simone Cialdi and Davide Brivio and Matteo G A Paris},
journal= {arXiv preprint arXiv:1007.0505},
year = {2015}
}