Investigations On Multienergy Coherent Atom Localization And Photonic Manipulation

With the development of laser technology and micro processing technology,quantum coherence effect has attracted wide attention.Based on the quantum coherence effect,many interesting optical phenomena have been realized,such as electromagnetically induced transparency,atom localization,sub-diffraction imaging,photon transmission,etc.The study of this phenomenon is beneficial to promote the development of quantum information and integrated optics.In this paper,we use the semi-classical theory of the interaction between light and matter and waveguide quantum electrodynamics theory to study the three-dimensional localization of coherent atoms and the transport properties of photons in network of quantum emitterswaveguides.The main research works include the following aspects:1)We present an efficient scheme to achieve high-percision three dimensional atom localization via measuring the population of excited state in a four-level ladder-type atomic system.We show that,the efficient multiphoton quantum destructive interference leads to multiphoton excitation of the excited state and the redistribution of the atom when the fluorescence emission has become sufficiently intense.The present results show that the fluorescence emission as well as the multiphoton quantum destructive interference can be modulated by adjusting the frequency detuning and phase shifts associated with the standing-wave fields,which can be well-understood by using fluorescence theory analysis.As a result,the atom can be localized at the certain position with a maximal precision is about0.02 λ when the system parameters are appropriate.Compared with the previous scheme,the percision is greatly improved.And the maximal probability of finding the atom at the certain position in three dimensional space can reach 100% in the present scheme.2)We investigate the non-reciprocal single-photon routing properties in two waveguides chirally coupled to a five-level atom and further realize the single-photon diode and circulator in the system.The single-photon diode can work simultaneously at three special frequency points and the diode is largely tunable by adjusting the system parameters.In addition,the non-reciprocity of the photon propagation can be turned on or off when the control fields are applied or removed.Furthermore,the single-frequency filter can be realized by modulating the detunings of the control fields.The single-photon circulator can achieve photon propagation in the pathways 1 →2,2 →3,3 →4 and 4 →1 with probability 100%.Then,we investigated the properties of single-photon transport via a network of three waveguides chirally coupled two two-level atoms.We study the properties of single-photon transport by adjusting the system parameters.A high-efficiency single-photon router can be realized when the chiral couplings are satisfied,and the photon can be completely routed to the determinate port of the selected waveguide by modulating the frequency of the incident photon and the waveguide–atom coupling strength.In addition,we find that the ratio of the chiral coupling strength can affect the reflection and transmission probabilities of the incident photon.By adjusting the ratio of the chiral coupling strength,the single photon has different transport properties.Furthermore,the efficiency of the single-photon router is affected little by the dissipation of the system in our scheme.Based on our scheme,the single-photon router can be easily extended to multiple waveguides.In conclusion,this thesis deepens our awareness and understanding of the localization of coherent atoms and photon transmission.These studies have great reference value for quantum optics,quantum information,integrated optics and other fields.