Research On Thermal-motion-induced All-optical Switching In Coupled Atom-cavity System

Nowadays,with the rapid development of the transformation of quantum information and quantum communication technology,new concepts such as quantum coherence,entanglement,and compression are gradually perceived by people.The interaction between light and atoms has become one of the more important research contents.The characteristics of regular thermal motion,the Doppler effect produced by it often becomes a characteristic that is not available in other experimental conditions,so that it can achieve many unique functions,such as optical isolation,all-optical switching,chiral materials,and so on.A three-level atom-cavity substitution system was used to conduct qualitative analysis of cavity transmission spectra.The research contents mainly include the following:Part 1: Some scientific backgrounds,principles and applications related to this system are briefly introduced.Part 2: Establish a ?-type three-level atom model,and experimentally study the cavity projection spectrum of the atom-cavity exchange system under different exchange field conditions.It was found that when the interchange field and the probe field propagate in the same direction,the cavity projection spectrum presents a three-peak structure,and the resonance center peak line width is extremely narrow,which is called the dark cavity polar peak.In the case of a standing wave conversion field,the dark state dipole peak is split into two peaks.It is said that by controlling the opening and closing of the conversion field,the conversion between the dark state dipole peak and the double dark state peak can be realized,and the all-optical switching is realized later In addition,the rule of experimental parameters such as light detuning,atomic number density and other experimental parameters in the lower cavity of the system were further explored experimentally.The results show that the frequency positions of the dark state polar peaks are then separated.In addition,by changing the atomic number density,the variation rule of the double dark state peaks is explored.It is found that the increase of the atomic number density is adopted and the atomic number density is changed.Large,dark-state peak intensity is continuously reduced,the distance is continuously increased,and at the same time,the Rabi sideband is continuously widened.Part 3: Construct a ?-type three-level atomic model.Starting from the system Hamiltonian,the derivation of the motion matrix equation of the atom density operator is used to solve the atomic density operator and the repolarization rate of the medium.The theoretical analysis of different coupling field conditions The absorption and dispersion characteristics of the cavity cavity mode of the probe cavity cavity cavity spectrum function were finally obtained.In addition,by changing the two experimental parameters of coupled optical detuning and atomic number density,the variation law of single dark state polar peaks and double dark state peaks in the cavity was theoretically calculated.The theoretical simulation and experimental results are in good agreement.Part 4: Based on the experiments in the second part,by dating an extra 852 pump field,whether it is injected into the cavity from the same direction or reverse direction,the dark state polaron peaks and double dark state peaks are amplified.Further,by changing the power of the pump field,the changing rules of dark state polar peaks and double dark state peaks were explored.On this basis,we control the opening and closing of the reverse conversion field by using an acousto-optic modulator(AOM)to achieve the control of a multi-channel,high-efficiency all-optical switch.