We report a direct measurement of the Wigner function characterizing the quantum state of a light mode. The experimental scheme is based on the representation of the Wigner function as an expectation value of a displaced photon number parity operator. This allowed us to scan the phase space point-by-point, and obtain the complete Wigner function without using any numerical reconstruction algorithms.
@article{arxiv.quant-ph/9903027,
title = {Direct measurement of the Wigner function by photon counting},
author = {K. Banaszek and C. Radzewicz and K. Wodkiewicz and J. S. Krasinski},
journal= {arXiv preprint arXiv:quant-ph/9903027},
year = {2008}
}