Quantum Control Of The Optical Properties In Semiconductor Microstructures

Quantum coherence,which plays an essential role in quantum optics,has been manifested in various branches of physics.In atomic,molecular,and optical physics,many phenomena subject to quantum coherence have been of considerable interest for many years.Such as electromagnetically induced transparency,high efficient four-wave mixing,giant Kerr nonlinearity,ultraslow optical soliton,enhancement of the refractive index,and so on.On the other hand,many kinds of nonlinear quantum optical phenomena based on the quantum interference in the semiconductor quantum wells and quantum dots have also been extensively studied in recent years,such as electromagnetically induced transparency,enhanced index of refraction,ultra-fast all optical switching,Kerr nonlinearity and other novel phenomena.In recent years,the semiconductor has been a popular research object,whether in light-emitting diode or photoelectric detection field,the special conductive characteristics of semiconductor attract a lot of researchers'attentions.In this paper,we mainly studied the optical characteristics of weak field in semiconductor microstructure.The enhanced refraction index without absorption easily realized via system parameters control.First of all,we investigate the quantum-interference effect on the refractive property in a coupled semiconductor quantum-dot nanostructure.It is found that the refractive properties can be significantly improved via the intensity and the frequency detuning of the coupling field as well as the field.However,our results are drastically different from those works.(1)We are interested in studying the controllability of the refractive properties in a semiconductor quantum-dot nanostructure of weak field.Especially the field takes part in the important role in the enhancement of refractive index without absorption.(2)We find that the positive or negative refractive index with vanishing absorption can be easily obtained in this semiconductor quantum-dot nanostructure,and the switch between positive refractive index and negative refractive index just by tuning the detuning of the controlling field and the incoherent pumping field.Next,we investigate the probe absorption of a weak probe field in two dimensions(the so-called two-dimensional probe absorption)in an asymmetric two coupled quantum wells.It is found that,due to the joint quantum interference induced by the standing-wave and coherent coupling fields,the probe absorption can be easily controlled via adjusting the system parameters in two dimensions.Most importantly,the pattern of probe absorption can be localized at a particular position and the maximal probability of finding the pattern in one period of the standing-wave fields reaches unity by properly adjusting the system parameters.Finally,we investigate the absorptive-dispersive properties of a weak probe field in a four-level asymmetrical double semiconductor quantum well.It is found that the enhanced refraction index without absorption can be easily controlled via adjusting properly the corresponding parameters of the system.Our scheme may provide some new possibilities for technological applications in dispersion compensation and solid-state quantum communication for quantum information processing.