Measuring nonclassical correlation of sub-picosecond pulsed mesoscopic twin-beam states

The robustness of nonclassical correlations exhibited by mesoscopic twin-beam states of light makes them useful for applications in the context of quantum technologies, such as for underwater quantum communication. To this aim, it is crucial to optimize the production of such quantum states of light, and study their level of nonclassicality in terms of different nonclassicality criteria. In this work, we realize an efficient source of well-populated twin-beam states in the red spectral region by pumping parametric down conversion with a natively sub-picosecond laser system. The nonclassical character of such states is investigated in terms of both the noise reduction factor and high-order correlation functions. The obtained results encourage the exploitation of this source in further optical schemes for practical applications.