Experimental characterization of multiple quantum correlated beams in two-beam pumped cascaded four-wave mixing process

We experimentally explore the relationships between the number of multiple quantum correlated beams generated by two-beam pumped cascaded four-wave mixing (CFWM) process and the system parameters, such as the angle between the two pump beams, one-photon detuning and two-photon detuning. We find that all of three system parameters can influence the number of multiple quantum correlated beams. Under the optimal system parameters, we can observe the emission of up to 14 quantum correlated beams with the intensity-difference squeezing of −6.29 ± 0.20 dB (−7.93 ± 0.64 dB after accounting for losses) from such CFWM scheme. Our results may find potential applications in building multi-user quantum network and multi-parameter quantum metrology.