We describe a simple and efficient setup to generate and characterize femtosecond quadrature-entangled pulses. Quantum correlations equivalent to about 2.5 dB squeezing are efficiently and easily reached using the non-degenerate parametric amplification of femtosecond pulses through a single-pass in a thin (0.1 mm) potassium niobate crystal. The entangled pulses are then individually sampled to characterize the non-separability and the entropy of formation of the states. The complete experiment is analysed in the time-domain, from the pulsed source of quadrature entanglement to the time-resolved homodyne detection. This particularity allows for applications in quantum communication protocols using continuous-variable entanglement.
@article{arxiv.quant-ph/0409211,
title = {Time-resolved homodyne characterization of individual quadrature-entangled pulses},
author = {Jerome Wenger and Alexei Ourjoumtsev and Rosa Tualle-Brouri and Philippe Grangier},
journal= {arXiv preprint arXiv:quant-ph/0409211},
year = {2009}
}