Quantum tomography of highly non-classical states of light field

We have reconstructed the quantum state of optical pulses containing single photons using the method of pulsed optical homodyne tomography. The single-photon Fock state was prepared via a conditional measurement on a photon pair generated in the process of parametric down-conversion. The angle-averaged Wigner function, determined with the efficiency of 55 %, shows a strong dip near the origin of the phase space reaching a negative value.