  We propose a procedure for tomographic characterization of continuous
variable quantum operations which employs homodyne detection and single-mode
squeezed probe states with a fixed degree of squeezing and anti-squeezing and a
variable displacement and orientation of squeezing ellipse. Density matrix
elements of a quantum process matrix in Fock basis can be estimated by
averaging well behaved pattern functions over the homodyne data. We show that
this approach can be straightforwardly extended to characterization of quantum
measurement devices. The probe states can be mixed, which makes the proposed
procedure feasible with current technology.

Quantum Physics