A novel method to detect quantum states of the radiation field

Summary

propose a new method for detecting the density matrix of the radiation field via optical homodyne tomography. The tomographic reconstruction is greatly improved, with very fast data analysis and very reliable statistics on Une with detection. The Wigner function of the input field is reconstructed also for quantum superpositions of states. We analyse the sensitivity of quantum tomography in detecting the photon number, the field quadratures, and the phase of radiation field. A comparison between results of quantum tomography and direct detection of these quantities (photodetection, single-homodyne detection, and double-homodyne detection, respectively), is given at fixed energy impinged into the experimental apparatus. We show that, despite tomographic reconstruction provides a complete characterization of the field state, it is more noisy than single-observable detection schemes.