Transmitted Probe Beams Research Articles

Theoretical Study of Spatial and Angular Goos-Hänchen Shifts in Quantum System

The behavior of the spatial and angular Goos-Hanchen (GH) shifts for the reflected and transmitted probe light beams is theoretically investigated in a fixed geometrical configuration containing the three and then four – level quantum dot nanostructure. It is found that, by adjusting the controllable parameters such as Rabi frequencies of applied fields, the spatial and angular Goos-Hanchen shifts can be controlled containing both of the positive and negative shifts of reflected and transmitted probe light beams. Moreover, we find that the simultaneous superluminal or subluminal light reflected and transmitted probe beams can be obtained through the medium.

Frequency shift of an optical cavity mode due to a single-atom motion

ABSTRACTUsing quantum coherence effects, we have developed a new technique of detection of motion of single atoms or ions in an optical cavity. We have theoretically demonstrated that the presence of a single atom or ion inside cavity leads to a shift in cavity frequency and phase of transmitted probe beams. It has been shown by the use of EIT technique, the change of the phase is extremely sensitive to probe detuning in the vicinity of resonance frequency and can be in the order of .

Implications of spectral hole burning on the manipulation of spatial Goos–Hänchen shift in an atomic cell

We present a new scheme to report on Goos–Hänchen (GH) shift experienced by the Gaussian light beam interacting with an optical cavity filled with four-level sodium atomic medium in the spectral hole burning region with and without Doppler broadening effect. Theoretical atomic density-matrix formalism is employed to obtain the susceptibility of atomic medium while the stationary-phase-theory is used to compute the GH shift in the reflected and transmitted probe beams subjected to control fields. A steep normal slope of dispersion is observed with a maximum and zero probability of transmission and reflection coefficients, respectively, at the regions of the spectral holes burning. In the normal dispersion spectrum at the region of spectral hole burning, positive and negative GH shift is observed, respectively, in the transmitted and reflected light beams. However, at anomalous dispersive regions negative GH shift in the transmission beam and positive GH shift in the reflection beam is observed. The reflection and transmission coefficients as well as the spatial GH shift are the functions of probe detuning, collective phase of control fields, beam incident angle and inverse Doppler broadening effect in the spectral hole burning region. The position and number of spectral holes also depend on the same spectral parametrs as stated above. The study is expected to be useful for optoelectronic devices and optical-clocking applications.

Controlling Goos-Hänchen shifts due to the surface plasmon effect in a hybrid system.

We have theoretically studied the Goos-Hänchen (GH) shifts of both the reflected and transmitted probe beams emerging from a cavity consisting of a hybrid system of a coupled quantum dot (QD) nanostructure and a metallic nanoparticle (MNP). It is realized that the GH shifts in the transmitted and reflected light beams can be enhanced due to the surface plasmon effect in the MNP. Also, it is shown that by adjusting the distance between QD and MNP and polarization control between probe field and major axis of the hybrid system, the simultaneous negative and positive GH shifts in reflected and transmitted light beams can occur. Moreover, the effects of the intensity and detuning of the coupling light on the GH shift properties of the reflected and transmitted lights have been discussed. We have found that under different parametric conditions of the hybrid system, the GH shifts of the reflected and transmitted light beams can be adjusted by tuning the intensity and controlling the detuning of the coupling field. The results show that our proposed model may be used for future optical sensor devices based on MNP hybrid systems.

Phase control of Goos-Hänchen shifts in a four-level quantum dot nanostructure

In this letter, phase control of the Goos-Hänchen shifts of the reflected and transmitted probe light beams through a cavity containing four-level InGaN/GaN quantum dot nanostructure is theoretically discussed. In order to achieve the wave functions and their corresponding energy levels of the mentioned quantum dot nanostructure, Schrödinger and Poisson equations must be solved in a self consistent manner for carriers (here electron) in quantum dot. It is found that the coupling field, the pumping field as well as the cycling field can enhance the GH shifts of the reflected and transmitted probe beams. The effect of relative phase and the detuning of the probe light on the GH shifts of the reflected and transmitted probe beams are also investigated. We find that the GH shifts can be switched between the large positive and negative values by adjusting the controllable parameters.

Plasmonic structure induced giant Goos–Hänchen shifts in a four-level quantum system

In this study, we explore the role of plasmonic nanostructure on Goos–Hänchen (GH) shifts of the reflected and transmitted probe beams. We suppose that the intracavity medium is consisted of four-level quantum system and plasmonic nanostructure which located at distance d from quantum system. We show that in the presence of plasmonic nanostructure the giant GH shifts obtain in reflected and transmitted light. Moreover, it is finding that the group velocity of the reflected and transmitted light can be switched from slow to fast light simultaneously.

Incoherent control of Goos–Hänchen shifts in a four-level InGaN/GaN quantum dot nanostructure

In this paper, we propose a new configuration for manipulating Goos–Hänchen (GH) shifts in reflected and transmitted probe beams in a fixed geometrical scheme with a confined four-level InGaN/GaN quantum dot nanostructure. Here, the four-level quantum dot nanostructure is driven by a weak probe light, a coherent coupling field, and two broadband polarized fields that serve as the incoherent pumping fields. We theoretically show that by modulation of the external coupling field, incoherent pumping rates, and detuning of the probe light, the GH shifts in the reflected and transmitted probe light can be controlled. Our results show that enhanced GH shifts of reflected and transmitted probe beams can be obtained by simultaneous use of incoherent pumping rates and detuning of the probe light. Moreover, we find that the GH shifts in both reflected and transmitted probe beams can be negative or positive at certain angles of the incident probe field. Thus, these results may provide some new possibilities for technological applications in all-optical systems based on nanostructure devices.

Goos-Hänchen shifts in a four-level quantum system near plasmonic nanostructure

Goos-Hänchen (GH) shifts of the reflected and transmitted probe beams through a cavity with a four-level quantum system and plasmonic nanostructure is investigated. It is realized that for different values of distance between plasmonic nanostructure and quantum system, the negative and positive GH shifts of the reflected and transmitted probe beams can be controlled. In addition, it is found that the relative phase of applied fields in the presence of plasmonic nanostructure can be used as an important parameter for controlling the GH shifts in reflected and transmitted light through the cavity. Moreover, the distance effect between four-level quantum system and plasmonic nanostructure has also been discussed on lateral shifts of reflected and transmitted light.

Phase control of Goos–Hänchen shift via biexciton coherence in a multiple quantum well

The behavior of the Goos–Hänchen (GH) shifts of the reflected and transmitted probe and signal pulses through a cavity containing four-level GaAs/AlGaAs multiple quantum wells with 15 periods of 17.5nm GaAs wells and 15-nm Al0.3Ga0.7As barriers is theoretically discussed. The biexciton coherence set up by two coupling fields can induce the destructive interference to control the absorption and gain properties of probe field under appropriate conditions. It is realized that for the specific values of the intensities and the relative phase of applied fields, the simultaneous negative or positive GH shift in the transmitted and reflected light beam can be obtained via amplification in a probe light. It is found that by adjusting the controllable parameters, the GH shifts can be switched between the large positive and negative values in the medium. Moreover, the effect of exciton spin relaxation on the GH shift has also been discussed. We find that the exciton spin relaxation can manipulate the behavior of GH shift in the reflected and transmitted probe beam through the cavity. We show that by controlling the incident angles of probe beam and under certain conditions, the GH shifts in the reflected and transmitted probe beams can become either negative or positive corresponding to the superluminal or subluminal light propagation. Our proposed model may supply a new prospect in technological applications for the light amplification in optical sensors working on quantum coherence impacts in solid-state systems.

Controlling of Goos-Hänchen shift via biexciton coherence in a quantum dot

Controlling of the Goos-Hanchen (GH) shifts of the reflected and transmitted probe pulses through a cavity containing four-level GaAs/AlGaAs quantum dot with 15 periods of 17.5 nm GaAs wells and 25-nm Al0.3Ga0.7As barriers is investigated. Under appropriate conditions, the probe absorption can be converted to the probe gain, therefore, the controlling of negative and positive GH shift in the both reflected and transmitted probe beams can be occurred simultaneously. Our obtained results show that the group index of the probe beams could be negative or positive in both reflected and transmitted pulses. Therefore, simultaneous subluminal or superluminal light propagation in reflected and transmitted pulses can be achieved.

Enhancement of the Goos–Hänchen shift by electromagnetically induced transparency with amplification

The manipulation of the Goos–Hänchen (GH) shifts of the reflected and transmitted probe beams through a cavity containing ∆-configuration artificial or realistic atomic medium is investigated. Adjusting the coherent control fields of atomic medium, the electromagnetically induced transparency with amplification (EITA) can be yielded. When the frequency of probe beam is around EITA, the negative as well as positive GH shifts of the reflected and transmitted probe beams can be greatly enhanced by EITA. Meantime, the GH shift can be switched between the considerably large positive and negative values by adjusting the collective phase of the external fields.

Control of the Goos-Hänchen shift of a light beam via a coherent driving field

We present a proposal to manipulate the Goos-H\"anchen shift of a light beam via a coherent control field, which is injected into a cavity configuration containing the two-level atomic medium. It is found that the lateral shifts of the reflected and transmitted probe beams can be easily controlled by adjusting the intensity and detuning of the control field. Using this scheme, the lateral shift at the fixed incident angle can be enhanced (positive or negative) under the suitable conditions on the control field, without changing the structure of the cavity.