Preparation Of Antibunched Photon Pair/Triplet Based On Photon Blockade Effect

Correlated photon pairs are an important quantum resource,not only often used in quantum information and quantum communication,but also have high application value in other fields,such as improving the resolution of biological microscopes.High purity,high brightness and strong correlation are the main concerning for preparing high-quality photon pairs.The quality of correlated photon pairs prepared based on different physical phenomena varies greatly,and the photon blockade effect is one of the important ways to improve the purity of photon sources.This thesis discusses the preparation of correlated photon pairs/triplets based on photon blockade effect.First,we theoretically explore a model of intracavity parametric down-conversion process to prepare antibunched photon pairs.In the down conversion process,it can be considered that two down converted photons are generated at the same time,so the output two photons have a strong time correlation.To improve the purity of the photon source,the anharmonicity of the energy level of the dressed state formed by the cavity mode is used to realize the conventional photon blockade.The results show that the output photon pairs have higher purity.Then we explore another method to generate antibunched photon pairs.Here the model considered is a coupled Jaynes-Cummings(JC)models.The coupling between the two optical cavities in the system will change the conditions for an individual JC model to produce the photon blockade effect.Meanwhile,this coupling effect will lead synchronization between the different intracavity photons,which leads to the output photons temporal correlation.The correlated photon pairs prepared by this scheme have higher purity and strong temporal correlation.The above discussion mainly concerns the preparation of antibunched photon pairs.Now we further study the preparation of antibunched photon triplet.The used physical model is three-mode light fields interacting with the inverted tripod type four-level atom.After analytical calculation,we obtain the condition for the three different cavity modes being simultaneously blockaded.Under this condition,the third-order cross-correlation between three modes is greater than 1.Therefore,we propose an antibunched photon-triplet source with strong time correlation.