Algebraic Operation Of Optical Orbital Angular Momentum Based On Slow-light Four-wave Mixing In Solid State EIT System

The birth of quantum mechanics has profoundly changed and affected people’s thinking and lifestyle,and it will continue to play an immeasurable role in the transformation of human society.At present,we are in the period of "the second quantum revolution".The emerging field represented by quantum information science has entered a new stage of rapid development.Especially,the development of quantum communication and quantum network has become one of the hot topics that researchers all over the world pay attention to.The development of quantum communication and quantum network urgently needs a new method to transmit and process quantum information in a controllable way.As we know,light has the characteristics of fast transmission speed,strong antiinterference ability and high bandwidth,and is considered to be an excellent carrier of information transmission.Therefore,optical quantum communication and information processing have received considerable attention.In recent years,optical vortices have become an important optical field that has been continuously concerned and studied by people.Because of its special wavefront structure,which can carry orbital angular momentum,its topological stability,the orthogonality between different orbital angular momentum quantum states and many other superior characteristics,it can be used to build high-dimensional quantum communication networks,which greatly improves the channel capacity and security of communication.Therefore,the vortex light carrying orbital angular momentum is considered as an excellent resource for realizing quantum communication.In order to realize quantum communication,it is necessary to transmit and process the quantum state information carried by the vortex light.The interaction between light and atoms makes it possible to achieve the above purpose.As we all know,electromagnetically induced transparency(EIT)based on the interaction between light and atoms is an important tool for manipulating light fields.People are more and more interested in manipulating optical orbital angular momentum(OAM)using EIT technology.In coherently driven media,the coherent operation of OAM based on EIT is very useful for information processing and communication,so it is necessary to develop OAM operation in different experimental media for its further application.Solid state media provide a space fixed interaction unit,which has the advantages of small size,easy integration,easy portability,etc.,so coherent driven solids have more practical applications than atomic gases.In the study,the solid medium we used is rare earth doped crystal,which is composed of rare earth ions and host crystal.The more common host crystal is yttrium silicate(Y2SiO5)crystal.In the experiment,it is required that there is a strong interaction between light and matter,and the host crystal doped with rare earth ions provides the possibility to achieve the above purpose.In rare earth doped crystals,an ensemble composed of rare earth ions can be formed.It has been shown that when N rare earth ions are doped in the crystal,the coupling degree between light and atom can be improved to(?)times of the original[1].In the experiment,the rare earth doped crystal we used is praseodymium doped yttrium silicate(Pr3+:Y2SiO5)Crystal,We will realize the control of vortex optical OAM based on the EIT effect in Pr3+:Y2SiO5 crystal.EIT is an effective method of light field manipulation.Because of its induced destructive quantum interference,EIT makes the opaque medium transparent to the detection field and allows extensive interaction between light and matter.We have noticed that in previous studies,the processing of vortex optical information requires a storage and release process,which will affect the processing efficiency and fidelity of optical information to a certain extent.In order to overcome this,in the experiment,In order to overcome this,in the experiment,we used the nonlinear crystal Pr3+:Y2SiO5,the slow light four-wave mixing(FWM)process based on EIT realizes the manipulation of OAM,and the algebraic operation of OAM is realized on this basis.In this process,the optical information can be processed without the storage and release of light.This will further enrich the application of the integer topological charge factor of optical vortices in topological mathematics,quantum calculation and processing.Our relevant research will enable people to better understand the interaction between OAM and matter.These manipulations of OAM may also have important potential value in optical signal processing and quantum information science,and have practical significance for promoting the further development of quantum information science.