Research Of Electromagnetically Induced Transparency Absorption And Dispersion

Electromagnetically induced transparency(EIT) is a kind of nonlinear optical effect which is the result of interaction between light and matter. It’s a quantum effect that permits the propagation of light pulses through an otherwise opaque medium. Because of its high transmission rate, deeply change of dispersion and nonlinear effect, it has especially attracted much attention over the past two decades. This phenomena is widely used to realize the reduction of light pulse, light storage and the quantum information process,In this paper, our main work is the study of the absorption and dispersion properties of EIT in thermal atomic ensemble and the realization of a preliminary quantum information storage process by the EIT phenomenon in cold atomic ensemble, as follows:(1) The phenomenon of electromagnetically induced transparency(EIT) in85 Rb atomic vapor is studied in a Λ-type of four-level system with the coupling laser frequency being detuned near the atomic resonant frequency. To explain the experiment result, we demonstrate that it is a result of combined effect of two excited states and analysis it with the theory of four-level system. The trend of theoretical simulation and experimental result is basically the same.(2) A Mach-Zehnder interferometer is set up to study the absorption and dispersion in a Doppler-broadened Λ-type three-level system by stimulated Raman spectroscopy(SRS) with homodyne detection. And prove the dispersion and absorption are related by the Kramers-Kronig(KK) relation.(3) Optimize the experimental construction of the quantum optical storage system and optimize the experimental parameters which affect the trapped cold atoms. Carry out the experiment of quantum information storage. Besides, with the method of side-band locking,we obtain two kinds of light with a frequency difference of 6.8 GHz, and lay the foundation for a Λ-type of EIT signal storage.