A review on recent results on on/off reconstruction of optical states

The knowledge of the density matrix of a quantum state plays a fundamental role in several applications, from quantum information to Standard Quantum Mechanics foundations investigation. Recently, a method has been implemented in order to obtain the reconstruction of the (diagonal) elements of the density matrix exploiting the information achievable with realistic on/off detectors (e.g. silicon avalanche photo-diodes). Purpose of this paper is to introduce this on/off method and present the last experimental results obtained with it in several different cases.