Manipulation And Application Of Light's Orbital Angular Momentum

Recent years,as a new degree of freedom of photon,Orbital Angular Momentum(OAM)have been widely studied in classical and quantum information areas.Photon's Spin Angular Momentum(SAM)originates from the polarization of the beam,while pho-ton's OAM is related to the helical phase front of the beam,so the beam carrying OAM is also called optical vortex.The single photon's SAM(±h)can be used to achieve only two-dimensional information coding,while the OAM(±lh)theoretically have no boundary on the information coding,thus it provides an exciting application prospects for massive information encoding with a single photon.However,the studies of OAM still need explo-ration and discovery.In this PhD thesis,the research are mainly focus on the generation,separation,detection and novel application like image coding and sensing of photon's OAM.Hopefully it will broaden the application of photon's OAM in both classical and quantum information.Firstly,the studies begin with the classical manipulation of OAM,which con-tains:(1)Research on the production Technology of High order OAM using a single spatial light modulator in laboratory.This provide a new solution for High order OAM production and manipulation;(2)Mimicking Faraday Rotation to Sort the OAM as well as fractional optical vortex of Light,the method may be useful for expanding the OAM demultiplexing technique significantly;(3)a new scheme of high efficiency detecting optical vortex with a small number of photon is proposed,which provides a solution for vortex detection at pho-ton count level.Secondly,the researches are focused on the application of OAM.Firstly,the classical application:(1)Based on digital spiral imaging technology,an image encoding and decoding method based on OAM mode conversion is proposed.This method provides a new view for optical image encryption and decryption.The diffraction theory of OAM beam from near field to far field is also studied,which provides a new analytical method for aperture diffraction with symmetrical structure.(2)The author builds a 120m free s-pace link and implemented the detection of the rotation speed and rotation symmetry of the object by using the photon's OAM.The technology is expected to construct a new type of remote object speed sensor,which has important practical significance for remote sensing technology based on OAM.On the other hand,for quantum information application:(1)the author builds the ghost imaging setup and coincidence measurement setup systematically and used them to realize the quantum version of the rotation Doppler effect,it is of great significance to realize the sensitive detection of the angle of the non-contact rotating object;(2)By changing the transverse coherence of the pump beam,the entanglement character-istics of the down converted photon pairs in momentum and position are carefully studied,which is very significant to understand the relationship between pump beam and two-photon entanglement.Finally,the author gives a summary and prospect of the whole thesis.In a word,this PhD thesis involves many fields of photon's OAM,it is hope that this thesis will give a good reference for the study of photon 's OAM.