Experimental implementation of the multifunctional compact two-photon state analyzer.

We report on experimental implementation of a multifunctional two-photon state analyzer. The device aims to be compact and able to provide several important characteristics about any two-photon quantum state. It operates in two modes: first mode is the two-photon interference analysis giving the information about spectral properties of the photons and the degree of mutual indistinguishability. The second mode provides polarization analysis and complete two-photon state tomography. Density matrix estimated from the tomography data reveals namely the quantum state purity or negativity. This device was tested on the photon pairs generated by the Kwiat source.