Precise information about the temporal mode of optical states is crucial for optimizing their interaction efficiency between themselves and/or with matter in various quantum communication devices. Here we propose and experimentally demonstrate a method of determining both the real and imaginary components of a single photon's temporal density matrix by measuring the autocorrelation function of the photocurrent from a balanced homodyne detector at multiple local oscillator frequencies. We test our method on single photons heralded from biphotons generated via four-wave mixing in an atomic vapor and obtain excellent agreement with theoretical predictions for several settings.
@article{arxiv.1405.6251,
title = {Complete temporal characterization of a single photon},
author = {Zhongzhong Qin and Adarsh S. Prasad and Travis Brannan and Andrew MacRae and A. Lezama and A. I. Lvovsky},
journal= {arXiv preprint arXiv:1405.6251},
year = {2015}
}
Comments
8 pages, 6 figures. Accepted by Light: Science & Applications. In press