Study On The Modulating Amplitude Of The Storage And Retrieval Of Optical Soliton In GaAs Quantum Dots EIT Medium

Up to now,the best carrier of the propagating information in quantum communication transmission technology is photon.However,in the process of the information propagation carried by photon,the amount of the information appears distorted due to dispersion and diffraction of the photon.Compared with photon,optical soliton is the product of the balance after the interaction between dispersion or diffraction effect of the medium and nonlinear effect of the system.It has higher stability and fidelity and is a more ideal information carrier.So far,it is theoretically predicted that the storage and retrieval of optical solitons can be realized in the ultracold atomic electromagnetically induced transparency(EIT)medium.However,the conditions of realizing ultracold atom EIT medium are very harsh,which requires low temperature(close to absolute zero)and sparsity.Therefore,it is a great challenge to apply it to practical application.Moreover,the equipment for optical quantum information storage and retrieval in ultracold atomic media is also huge,complex and expensive,which runs counter to the development direction of small-scale integration.Fortunately,semiconductor quantum dots,also known as ‘artificial atoms’,not only have excellent characteristics such as high nonlinear effect,controllable parameters and easy integration,but also have been explored to realize optical solitons in the system.Based on this,the storage and retrieval of optical solitons in semiconductor quantum dot EIT media and their modulating amplitude are studied in this paper.The main research contents are as follows:1)Considering that the probe and control field of different frequencies are coupled between different energy levels of the In As/Ga As single quantum dot EIT medium,ladder-type,Λ-type and V-type energy level configurations can be formed.Then,we study whether different energy level configurations of In As/Ga As single quantum dots can adjust the amplitude of the optical soliton storage and retrieval.It is shown that in the linear case,EIT windows can be formed in the ladder-type,Λ-type and V-type energy level configurations,and the width of the transparent window will increase with the increasing strength of the control pulse.For the nonlinear case,under the specific parameters of In As/Ga As single quantum dots realized in the existing experiments,the ladder-type and Λ-type energy level In As/Ga As single quantum dot system can not only form optical solitons,but also realize the storage and retrieval of optical solitons,and the fidelity of optical soliton storage and retrieval is higher than that of linear and strongly nonlinear optical pulses,However,In As/Ga As single quantum dot system with V-type energy level configuration has no soliton solution,which means that the system cannot form optical solitons under this condition.In addition,we also found that different energy level configurations can adjust the amplitude of optical soliton storage and retrieval.Due to the greater nonlinear effect in the Λ-type energy level configuration,the amplitude of optical soliton storage and retrieval in the Λ-type energy level configuration is higher than that in the ladder-type energy level configuration.2)Considering the inter-dot tunneling coupling in quantum dot molecular EIT medium,we studied how the inter-dot tunneling coupling in Ga As triple quantum dot(TQD)molecular EIT medium adjusts the amplitude of optical soliton storage and retrieval.For the linear case,there appears single(two)tunneling induced transparency(TIT)window caused by single(two)inter-dot tunneling coupling effect.Meanwhile,we also found that the width of both single and/or double TIT windows becomes wider with the increasing strength of single and/or double inter-dot tunneling coupling.For the nonlinear case,the stable propagation of soliton can be realized.We calculated that the threshold power of generating optical solitons is extremely low.Especially,we demonstrated that the storage and retrieval of optical solitons can be controlled by switching off and on single(two)inter-dot tunneling coupling effect.That is to say,both the formation of optical solitons and their storage and retrieval in an TQD molecule are caused by inter-dot tunneling coupling effect,different with that by the strong control optical pulse in ultra-cold atomic EIT media.In addition,we found that the strength of quantum inter-dot tunneling coupling can adjust the amplitude of optical soliton storage and retrieval.For the case that one(the another)inter-dot tunneling coupling is turned on(off),with the increasing strength of the inter-dot tunneling coupling,the amplitude of optical soliton storage and retrieval increases.For the case that two inter-dot tunneling coupling are turned on,with the increasing strength of the two inter-dot tunneling coupling,the amplitude of optical soliton storage and retrieval emerges a trend of first decreasing and then increasing.