Electromagnetically Induced Transparency In Open V-type Molecular System

Electromagnetically induced transparency makes the reso nantly-absorptive medium producing the transparent effect when the strong coherent control field exists in the quantum system. Thus, the phenomena of electromagnetic induced transparency has many pretty important applications in many ways, such as slowing down group velocity, coherent population trapping, the enhancement of Kerr nonlinearity,precision spectroscopy, precision measurement, and so on. Group velocity slowing phenomena based on electromagnetically induced transparency has great potential application in the quantum constraint systems.In recent years, researchers have achieved electromagnetically induced transparency successfully in the atom and semiconductor field. and the theoretical model is established to calculate and estimate the character of absorption and dispersion in theory, it is possible for further group velocity slowing effect based on electromagnetically induced transparency. Now physical model studied widely is three-level A-type atoms system, but actually we use molecular system, both level structure choice and the future of practical application have more potential in advance. Thus, we expound semiclassical theory that under the effect of light-matter interaction in this paper, base on three-level V-structure of sodium molecule, deduce density matrix equation of light-matter interaction and simulate the character of absorption and dispersion of electromagnetically induced transparency logically,realize group vetocity decrease of molecular system on this basis while introducing metal nanometer materials to optimize characteristics..This paper mainly studied the properties of Electromagnetically Induced Transparency, which is under V type molecular systems with reasonable theoretical derivation calculation and numerical simulation The main research contents are as follows:Firstly,based on the the atomic system as a pilot, the needed Theoretical Foundation was studied and on this basis, density matrix equation was derivated with the special structure of Na molecular medium was introduced, which was solved by perturbation approximation. The Electromagnetically Induced Transparency and group velocity slows phenomenon of the three-level V system of known structure were discussed.Secondly, for its openness, doppler broadening features, linear polarization,Particle population number, Index of refraction and Slow group velocity factor were Theoretical simulated. What's more, Control field strength and Detuning influence were discussed in detail and the feasibility of group velocity slow of the molecular system is verified.Finally, the Na molecules model is optimized by introducing the characteristic of EIT effect, by introducing nanometer material to the system to carry out correction,and explored the influence of detection field on dielectric absorption and d:ispersion characteristics, when the characteristic spectrum no longer has a symmetrical characteristic spectra, the line width became smaller and the peak value increased simultaneously,which gives a remarkable improvement of the EIT efficiency of the molecular system. Then carried on a theoretical simulation about group velocity slow changing factor which has a influence on slow light conditionality. Compared and analysed the scheme with Na molecules system.