  For the visualization of quantum states, the approach based on Wigner
functions can be very effective. Homodyne detection has been extensively used
to obtain the density matrix, Wigner functions and tomographic reconstructions
of optical fields for many thermal, coherent or squeezed states. Here, we use
time-domain optical homodyne tomography for the quantum state recognition and
reconstruction of the femtosecond optical field from a nonequilibrium
superradiant coherent electron-hole state formed in a semiconductor laser
structure. We observe severe deviations from the Poissonian statistics of the
photons associated with the coherent laser state when the transformation from
lasing to superradiance occurs. The reconstructed Wigner functions show large
areas of negative values, a characteristic sign of non-classicality,
demonstrating the quantum nature of the generated superradiant emission. The
photon number distribution and Wigner function of the SR state are very similar
to those of the displaced Fock state
