Research For Manipulating The Joint Spectrum Of Biphoton And The Characteristic Of Filtering Remaining Pump Light

Quantum clock synchronization technology is currently the most exact clock synchronization technology in theory. To achieve such a high precision clock synchronization technology, the first and most important work we must do is to obtain quantum frequency-entangled source of good performance. Researches show that the frequency entanglement characteristic of quantum frequency-entangled source is directly associated with the joint spectrum of quantum state. Therefore, it’s helpful for us to obtain special frequency-entangled source by studying the factors that affecting the joint spectrum of quantum state and then manipulating these physical factors. At the same time, exploring and seeking better theory and methods to optimize the quantum clock synchronization frequency-entangled source has also become a key.Considering the generation theory and methods of quantum frequency-entangled light source, this thesis studies and discusses how the spatial distribution of the pump light, the length of nonlinear crystal, the emission angle of photon pairs and the beam collection radius influence the frequency entanglement characteristic of the frequency-entangled light source via the SPDC. Meanwhile, we also analyzes the filter efficiency caused by the filters that filtering the remaining pump light, and verified it by experiment.The main accomplished work contains two sections. Firstly, based on the spatial distribution of the pump light, combined with the length of crystal, the emission angle of photon pairs and the beam collection radius, we theoretically analyzes how these physical parameters influence the frequency entanglement characteristic of the frequency-entangled light source. The results show that by using the Spatial-to-Spectral Mapping technique of changing certain critical parameters, we are able to effectively prepare special frequency-entangled light source. Second, under the condition of the788nm broadband pulsed pump light via SPDC process, with the light spectrum distribution and the filters characteristic parameters, we analyzes the filter efficiency caused by the various types of filters filtering the remaining pulse pump. In addition, through experiments and data processing, we verifies the validation of this conclusion, which provides a theoretical guidance for quantum correlated measurement of frequency-entangled source via SPDC process.