Nonreciprocal Unconventional Photon Blockade

Reciprocity is a basic principle in optics and requires systems to have exchange symmetry.When the positions of stimulus port and the response port is exchanged,the response of the transmission channel is symmetrical.It has important implications,and places fundamental restrictions on the way optical signals are processed.However,researchers found that nonrecip-rocal devices that break this exchange symmetry have many advantages in communication,such protecting the light source from the effects of reverse noise i.e.,isolators and circulators,and such devices have also become basic devices in photonics system.Early nonreciprocal devices were mainly based on magneto-optical effects,but such devices had large power consumption and were cumbersome to integrate.Then researchers found that nonlinearity and space-time modulation and other systems can overcome the above short-comings and make nonreciprocal devices toward integrated chips.However,most of the recent nonreciprocal studies have mainly focused on classical transmission,and pure quantum nonreciprocal devices have received little attention.Quantum information has been developing rapidly in recent years.Quantum communication requires a single photon source.Photon blockade has received widespread attention as a method that can produce a good sin-gle photon source,and a variety systems of photon blockade are emerging in the future.This paper combines the two to study the pure nonrecipro-cal quantum effect i.e.,nonreciprocal unconventional photon blockade.The main research contents are as follows:The first chapter mainly introduces the concept of photon blockade and nonreciprocity,its development process and recent research status.The second chapter mainly introduces some basic knowledge of photon blockade.The third chapter focuses on pure quantum nonreciprocal effects,named as nonreciprocal unconventional photon blockade.This paper study the ef-fect of rotation on photon blockade in coupled optical systems.Rotating cavity technology has been used experimentally for the study of nonrecipro-cal light transmission in optical cavity,but it has not been studied to com-bine it with weak nonlinearity to explore the quantum nonreciprocal effect.We found that the Sagnac effect caused by rotation can cause nonrecipro-cal photon blockade.Due to the rotation,we can achieve a strong photon blockade when the system is input from the left while photon bunching effect disappears when the light source from the right.Therefore,a pure quantum nonreciprocity is observed.Physically,when light enters the system from the left,the two-photon states of different channels undergo destructive in-terference which lead to photon blockade.In contrast,when the system is driven from the right side,the destructive interference effect disappear and the photon blockade effect disappear.Finally,we also explored the effect of temperature on the nonreciprocal quantum effect in the paper,and found that the increasing the dissipative of the cavity the temperature of nonre-ciprocal disappearance would increase significantly.This kind of quantum non-reciprocal device is particularly useful in achieving non-reactive quan-tum sensing or chiral photon communication.Chapter 4 is the summary and prospect of the full text.