Quantum-optical process tomography using coherent states.

We review the method for characterizing, with arbitrarily high accuracy, any quantum optical process, which our group has developed over the past few years. Our protocol recovers complete knowledge of the process by studying, via homodyne tomography, its effect on a set of coherent states, that is, classical fields produced by common laser sources. We present a simple scheme for calculating the process matrix from this information. We demonstrate the capability of our protocol by demonstrating complete characterization of an optical memory based on electromagnetically induced transparency. [ABSTRACT FROM AUTHOR]