Research On Controlling Diffraction Based On The Electromagnetically Induced Grating In Semiconductor Quantum Well

As a new type of semiconductor nanomaterial,semiconductor quantum wells have great significance in building high integrated circuits,constructing all-optical networks and realizing high-efficiency optical interconnections.The semiconductor quantum well structure is flexible in design,easy to control and integrate,and has broader prospects than atomic systems.Therefore,many researches on quantum coherence effects realized in atomic structure systems are extended to solid-state quantum systems such as semiconductor quantum wells.Quantum well materials have become highquality materials for studying quantum coherence and other effects.In recent years,the controllable electromagnetically induced grating(EIG)based on semiconductor quantum well has been concerned extensively by researchers.Compared with traditional gratings,this kind of gratings can realize the efficient and accurate control of the beam,and have greater flexibility and maneuverability.It has an excellent performance in the development of new optoelectronic devices and the improvement of optical communication.In this thesis,the standing-wave coupling field is utilized to replace the travelingwave field of electromagnetically induced transparency(EIT)in the quantum well system and the Raman gain effect is applied to realize one-dimensional and twodimensional EIGs.This grating is a hybrid of gain grating and phase grating.It is different from other gratings based on EIT and can not only effectively diffract the probe field to higher-order directions but also amplify the intensity of high-order diffraction,which greatly improves the efficiency of diffraction.Through specific analysis of the influence of each controllable parameter on the diffraction of the probe field,the conditions for the maximum intensity of each order diffraction are determined,and the dynamic and effective control of the diffracted light field is realized.In this thesis,we first describe the development trend of semiconductor quantum wells,introduce the structure and properties of semiconductor quantum wells,briefly describe the development status of EIT and EIG based on quantum coherence,and introduce the related theories needed in this thesis in detail.Then,a theoretical model is established in the four-level asymmetric semiconductor quantum well structure,and a one-dimensional EIG is constructed using a one-dimensional standing-wave field perpendicular to the probe field,the modulation effect of amplitude and phase in the grating is analyzed.Research shows that such grating not only amplifies the zero-order diffraction intensity,but also amplifies all high-order diffraction intensity as a whole.In addition,we can adjust the controllable parameters so that the diffraction field can show a uniform distribution while achieving the amplification effect,which is of great significance for realizing a high-efficiency amplification beam splitter.Finally,the standing wave is extended to the two-dimensional situation,and the influence of various parameters on the diffraction intensity distribution is analyzed in detail,and the parameters are appropriately selected to control the diffraction efficiency of the twodimensional grating to obtain a two-dimensional grating with high diffraction efficiency.Compared with other systems,the system in this thesis has higher conversion efficiency in high-order diffraction,can dynamically control the diffraction intensity of the light field,and control the intensity of each order diffraction more accurately.The research of high diffraction efficiency EIG based on semiconductor quantum well structure has application value in grating diffraction,new quantum devices,alloptical information processing,quantum communication and so on.