A quick-test method for the two-photon spectral correlation quantification

We propose a quick-test method for the two-photon spectral correlation quantification based on a dual-channel filter and a dispersive element, where the spectral correlation coefficient can be readily evaluated from directly measurable parameters in a coincidence measurement. Verified experiments have been conducted on two biphoton sources with different types of spectral correlation, presenting nice agreement with the joint spectrum measurement. Because of its simple implementation and fast measurement within seconds, this scheme is promising to be a plug-and-play tool for spectral correlation quantification, which would facilitate various quantum information applications with on-demand spectral correlation.