Experimental generation of multimode quantum correlations between a conical probe and a conical conjugate based on a four-wave mixing process

Multimode quantum correlations and entanglements has drawn much attention recently due to its importance for both fundamental science and the future development of quantum information processing and quantum communication. Here, by using a four-wave mixing process with a conical pump beam and a conical probe beam, we experimentally generate the multimode quantum correlations between a conical probe beam and a conical conjugate beam, and we also observe about -2.6-dB intensity-difference squeezing between these two conical beams. In addition, we find the optimal value of each parameter in this scheme for further applications. Besides, the multi-spatial-mode nature of the generated quantum correlated beams is shown by comparing the variation tendencies of the intensity-difference noise of the probe and conjugate beams under global attenuation and local cutting attenuation. Our scheme may find potential applications in quantum information processing and quantum communication.