Experimental Research Of The Four-wave Mixing Based On A Cavity-atom System

With the development of semiconductor lasers and cold atom technology,Cavity-QED based on atom-nonlinearity has been greatly developed in recent years.The strong coupling of atoms and cavities can be achieved experimentally by Cavity-QED.It can effectively improve the atomic optical thickness,enhance the coherent interaction between cavity modes and atoms,and provide a new platform for the study of atomic coherence.In the experimental study of the thermal atom-cavity coupling system,most of them are carried out in the ? type three-level atom and the annular cavity coupling system.The coupling field passed through the atomic medium singly and the cavity field(probe light)are propagating,avoiding the Doppler effect.In this paper,we mainly study the four-wave mixing effect of three-level atom and annular cavity coupling system,which mainly divided into three parts,the specific content is as follows:In the first part,made a brief introduction of several quantum effects of the atomic system and the atomic-cavity system.In the second part,the influence of optical pumping effect on the polarization characteristics of free space EIT medium is studied.In theory,considering the Doppler effect of atoms,the polarization characteristics of the atomic medium and the effect of the optical pumping effect on the polarization characteristics of the probe are analyzed when the probe lightand the coupled light are propagated and propagated in the same direction.The experimental results show that the effect of light pumping on the absorption characteristics of the probe in atomic medium has been successfully verified in free space.In the third part,the four-wave mixing effect of ?-type three-level thermal atom and annular cavity system is studied experimentally.The variation law of the reflection spectrum produced by the four-wave mixing effect with the frequency of detuning,power and particle density of the coupled optical frequency is discussed.Experiments show that the reflected four-wave mixing signal generated in the atomic resonance center can not start the vibration,which is insensitive to the cavity mode detuning,which is mainly due to the strong absorption caused by the pumping effect of the coupling field;however,in the single-photon detuning condition,due to the Doppler effect of the thermal atoms,the front and back coupling fields weaken the absorption of the cavity probe field and the reflected signal of the same frequency,so that it can start the vibration in the cavity,to obtain the narrow line width of the intracavity four-wave mixing signal,which provides a very important experimental guarantee and reference for our next step based on the cavity four-wave mixed signal correlation characteristics of the measurement and lumen-based stimulated Raman scattering.