Abstract We have proposed a new model for controlling the electromagnetically induced grating in a three-level closed-loop quantum system. The quantum system interacts with three-laser fields which one of them is the weak probe light and two of them are strong driving and coupling laser fields. These two strong laser fields have standing wave (SW) patterns in two x and y directions. This makes that the absorption and dispersion properties of the media change periodically which leads to diffraction of the transmitted light. We have shown that because of the closed-loop configuration of the quantum system the relative phase between applied lights can affect the diffraction grating pattern of the transmitted light. We have also discussed the Rabi-frequency effect of the driving and coupling lights on the different orders of the grating. We have shown that our proposed model may be used as a new tool for developing the future quantum information processing devices.
Abstract We have proposed a new model for controlling the electromagnetically induced grating in a three-level closed-loop quantum system. The quantum system interacts with three-laser fields which one of them is the weak probe light and two of them are strong driving and coupling laser fields. These two strong laser fields have standing wave (SW) patterns in two x and y directions. This makes that the absorption and dispersion properties of the media change periodically which leads to diffraction of the transmitted light. We have shown that because of the closed-loop configuration of the quantum system the relative phase between applied lights can affect the diffraction grating pattern of the transmitted light. We have also discussed the Rabi-frequency effect of the driving and coupling lights on the different orders of the grating. We have shown that our proposed model may be used as a new tool for developing the future quantum information processing devices.
Fraunhofer light diffraction of a weak probe field passing through an asymmetric three-coupled quantum well, which is driven by a standing wave and two coupling laser fields, is investigated. Depending on which transitions are coupled by the probe and standing field, two schemes are considered. It is demonstrated that owing to the closed-loop transition, optical properties and the diffraction pattern of the probe field in both schemes are highly affected by the relative phase of the applied fields and can be controlled by this parameter. Moreover, it is shown that the proposed schemes have multifunction capabilities. In the first scheme, as a result of varying relative phase, the electromagnetically induced absorption phase grating turns to the electromagnetically induced gain phase grating with remarkable efficiency, while in the latter scheme, a significant result is revealed: Tuning the relative phase can lead to inducing optical parity-time symmetry, which gives rise to an asymmetric diffraction grating. Such an all-optical phase-sensitive operation could be useful in optical switching and optical communications.
Abstract In this paper, we investigated electromagnetically induced grating in a three-level atomic system via relative phase between applied lights. The three-level atomic system interacts with a weak probe light, a signal light and a strong standing wave coupling light in two-dimensional directions. We realized that Fraunhofer diffraction pattern can be obtained by tuning the intensity and detuning’s of the coupling light. We also use of optical vortex light instead of optical plane wave and found that the asymmetric diffraction pattern can be obtained via orbital angular momentum (OAM), respectively. We also studied the different orders of the diffraction pattern versus relative phase of applied lights for different number of OAM.
Abstract The Fraunhofer diffraction pattern in a three-level quantum dot nanostructure is examined. A probe light, a two-dimensional standing wave field, and a weak signal light are the three optical laser fields that the graphene quantum dot interacts with them. The Fraunhofer diffraction pattern of the probe transmitted light has been addressed under two different coupling situations, including when the weak signal light into an optical vortex beam and a plane wave. The Fraunhofer diffraction pattern becomes symmetric for plane wave coupling light, and the diffracted light can be adjusted by the relative phase between applied lights. However, using the orbital angular momentum of light, it is possible to obtain an asymmetric diffraction pattern for optical light. It has been discovered that in both instances, phase modulation of the probe light’s transmission function allows the probe energy to move from zero order to higher orders.
Abstract A probe laser beam can be completely absorbed in an atomic resonance frequency region, however, if a coupling laser beam is further applied to the atom, the atomic medium can exhibit electromagnetically induced transparency, i.e the probe beam can be completely transmitted through the atomic medium. Thus, if the coupling beam is a standing wave field with nodes and antinodes, it will cause in space a periodic modulation of the transmitted spectrum of the probe field. This means that the probe field propagates through the atomic medium just as it passes through a diffraction grating which is called electromagnetically induced grating. Based on amplitude or phase modulation of transmission function, the absorption grating or the phase grating can be formed, respectively. In this work, based on controllable absorption and dispersion properties of a three-level V-type atomic system, we study the control of the absorption grating and the phase grating with respect to the intensity and the frequency of the laser fields. The absorption diffraction pattern at the two-photon resonance is obtained, while the phase diffraction pattern appears when there is a frequency shift of either the coupling frequency or the probe frequency compared to the corresponding atomic resonance frequency. By adjusting the coupling or/and probe laser frequency, the absorption grating can be converted into the phase grating and the high-order diffraction efficiency can also be improved.
Abstract In this paper, we suggest a theoretical model for creating a two-dimensional (2D) electromagnetically induced phase grating in a five-level quantum system interacting with a weak probe light, two coupling standing light in the x and y directions and a Laguerre–Gaussian (LG) field. By derivation of the Maxwell’s wave equation, we obtain the dynamic response of the probe light in the quantum system. Then, we perform the analytical solution of the probe susceptibility for obtaining the linear and nonlinear properties of the medium. By numerical calculations, we discuss the amplitude and phase modulations and Fraunhofer diffraction patterns of the probe light in different parametric conditions. We show that by adjusting the orbital angular momentum (OAM) of the LG light a 2D grating is observed. Moreover, we find that the probe energy can be transferred from zero order to high order of direction when we change the OAM number of LG light. Our proposed model may have potential applications in fundamental research and quantum information processing based on OAM light in quantum systems.
Abstract We theoretically study a two-dimensional electromagnetically induced phase grating in a four-level quantum system located near plasmonic metamaterials consisting of a periodic two-dimensional array of metal-coated dielectric nanospheres. The four-level quantum system interacts with a weak-probe laser field and a strong coherent coupling field with a standing-wave pattern. In the presence of plasmonic metamaterials the quantum system becomes sensitive to the relative phase between applied light. Therefore, the linear absorption and Kerr nonlinearity of the medium become phase dependent. Here, due to the standing-wave pattern of coupling light, an absorptive grating or phase grating can be formed in the quantum system. In our proposed model, we show that the diffraction efficiencies of the grating are related to the relative phase between applied fields, when the quantum system is located at different distances from plasmonic metamaterials.