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Photonic demultiplexer based on electromagnetically induced transparency resonances
摘要： We give an analytical and experimental demonstration of the possibility to realize a simple photonic demultiplexer based on electromagnetically induced transparency (EIT) resonances. The demultiplexer consists on an Y-shaped waveguide with an input line and two output lines. Each output line contains two grafted stubs at a given position far from the input line. We derive in closed form the expressions for a selective transfer of a single propagating mode through one line keeping the other line unaffected. We illustrate the analytical and numerical results by a simple experiment carried out using coaxial cables in the radio-frequency domain.
关键词： Coaxial cables,Y-shaped waveguide,EIT resonances,Photonic demultiplexer,Electromagnetically induced transparency
更新于2025-09-10 09:29:36
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Interaction-induced photon blockade using an atomically thin mirror embedded in a microcavity
摘要： Narrow bright or dark resonances associated with electromagnetically induced transparency play a key role in enhancing photon-photon interactions. The schemes realized to date relied on the existence of long-lived atomic states with strong van der Waals interactions. Here, we show that by placing an atomically thin semiconductor with ultrafast radiative decay rate inside a microcavity, it is possible to obtain extremely narrow dark or bright resonances in transmission. While breaking of translational invariance sets a limit on the width of the dark resonance width, it is possible to obtain a narrow bright resonance that is much narrower than the cavity and bare exciton decay rates and is protected against disorder by tuning the cavity away from the excitonic transition. Resonant excitation of this bright resonance yields strong photon antibunching even in the limit where the interaction strength is arbitrarily smaller than the non-Markovian disorder broadening and the radiative linewidth of the bare exciton. Our findings suggest that atomically thin semiconductors which exhibit large exciton-cavity coupling and small nonradiative line broadening could pave the way for the realization of strongly interacting photonic systems in the solid state.
关键词： electromagnetically induced transparency,photon blockade,photon-photon interactions,microcavity,atomically thin semiconductor
更新于2025-09-10 09:29:36
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Optical switching phenomenon in ladder type atomic system under varying wavelength mismatching effect with one due to a Rydberg transition
摘要： We present a theoretical study on probe field propagation through a three-level ? type system formed in an atomic vapor medium in presence of a strong control field. The model is based on density matrix method and is solved analytically, without neglecting any term in any power of probe and control Rabi frequencies, to find out the probe response under Doppler free condition as well as at room temperature. The probe response for a four-level ? type system is also determined analytically. Electromagnetically induced transparency is formed in the simulated probe response for both the level schemes. We also present the switching of probe field propagation from subluminal to superluminal as a function of probe detuning for different control transitions, one of which is to a Rydberg state. The switching window becomes asymmetric under detuned control field with the asymmetry depending on the wavelength mismatching factor between the control field and the probe field. Under strong probe regime probe propagation switches from superluminal to subluminal on resonance when the wavelength mismatch between the probe and the control field is increased, an effect which can be explained with the help of the analytical model that is free from any perturbative treatment.
关键词： wavelength mismatching effect,electromagnetically induced transparency,Rydberg state,optical switching,Ladder (?) type system
更新于2025-09-10 09:29:36
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Investigation of nonlinear absorption and the electromagnetically induced transparency in a SMNP-SQD hybrid system by using the Mie theory
摘要： By using the Mie theory, nonlinear absorption coefficient and electromagnetically induced transparency (EIT) of a hybrid system consisting of GaAs spherical quantum dot (SQD) with ladder model and parabolic potential in the vicinity of a spherical metal nanoparticle (SMNP) are investigated. The density matrix equations in steady-state are solved and the third order susceptibility is obtained. Then, by using imaginary part of third order susceptibility, the nonlinear absorption coefficient are computed. Then, the effects of radii of SQD and SMNP, distance between SQD and SMNP and control laser frequency on nonlinear absorption coefficient and electromagnetically induced transparency (EIT) are investigated.
关键词： Metal nanoparticle,Mie theory,Spherical quantum dot,Electromagnetically induced transparency,Absorption coefficient
更新于2025-09-10 09:29:36
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Azimuthal modulation of electromagnetically induced transparency using structured light
摘要： Recently a scheme has been proposed for detection of the structured light by measuring the transmission of a vortex beam through a cloud of cold rubidium atoms with energy levels of the Λ-type configuration [N. Radwell et al., Phys. Rev. Lett. 114, 123603 (2015)]. This enables observation of regions of spatially dependent electromagnetically induced transparency (EIT). Here we suggest another scenario for detection of the structured light by measuring the absorption profile of a weak nonvortex probe beam in a highly resonant five-level combined tripod and Λ (CTL) atom-light coupling setup. We demonstrate that due to the closed-loop structure of CTL scheme, the absorption of the probe beam depends on the azimuthal angle and orbital angular momentum (OAM) of the control vortex beams. This feature is missing in simple Λ or tripod schemes, as there is no loop in such atom-light couplings. One can identify different regions of spatially structured transparency through measuring the absorption of probe field under different configurations of structured control light.
关键词： orbital angular momentum,spatially dependent absorption,electromagnetically induced transparency,quantum interference,structured light
更新于2025-09-10 09:29:36
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Electromagnetically Induced Transparency In Rydberg Atomic Medium
摘要： Due to possessing big principal quantum number, Rydberg atom has some unique properties, for example： its radiative lifetime is long, dipole moment is large, and interaction between atoms is strong and so on. These properties make one pay attention to Rydberg atoms. In this paper we investigate the effects of Rydberg dipole-dipole interactions on electromagnetically induced transparency (EIT) schemes and group velocity in three-level systems of ladder type, which provides theoretical foundation for exploring the linear and nonlinear characteristics of light in a Rydberg electromagnetically-induced-transparency medium.
关键词： group velocity,Rydberg atom,electromagnetically induced transparency,dipole-dipole interactions
更新于2025-09-09 09:28:46
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A Group-Delay-Based Sensor Using Active EIT-Like Effect With Double Sensing Applications
摘要： A high-sensitive microwave sensor based on the variation of group delay is presented in this paper. The sensor is designed by mimicking the concept of electromagnetically induced transparency (EIT). The EIT-like effect that applied in the microwave circuit can provide a narrow transmission window in the stop band, which also brings ultraslow group velocity. Combined with the utilization of active resonator, the quality factor and group delay of the sensor are significantly enhanced. The active resonator is actualized by appending an active feedback loop that couples with the split-ring resonator of the EIT-like structure. The group delay of the active EIT-like sensor is particularly sensitive to the tiny phase variation of the active feedback loop, which is adopted to the high-performance sensing functions. The active EIT-like sensor with double sensing applications in this paper was fabricated and tested. The sensitivity of the proposed sensor is 0.012 pF/ns and 0.03 mV/ns, respectively.
关键词： sensing,active resonator,electromagnetically induced transparency (EIT),Group delay
更新于2025-09-09 09:28:46
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Frequency Selected Coherent Optical Storage Based on Electromagnetically Induced Transparency in Rubidium Vapor
摘要： Storage capacity is a key requirement for multiplexed quantum memory in long-distance quantum communication and quantum calculation. The data exchange and processing of a quantum system would speed up, with the bene?t from the increasing storage capacity. In this paper, we demonstrate a frequency selected optical storage based on the electromagnetically induced transparency scheme in warm atomic vapor. Two probe pulses with di?erent frequencies could be stored and retrieved in di?erent memory cell individually, in which the memory cells are divided by the velocity of atomic motion in Doppler broadening atomic vapor. The theoretical predictions show that the frequency bandwidth of the proposed multiplexed optical storage is decided by the width of Doppler broadening and the frequency bandwidth of each memory cell is decided by the width of electromagnetically induced transparency window. The proposed frequency selected storage signi?cantly advances the pursuit of multiplexed optical memory and should have important applications in classical and quantum information processing.
关键词： electromagnetically induced transparency,storage,optical,Doppler broadening
更新于2025-09-09 09:28:46
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Control of electromagnetically induced grating by surface plasmon and tunneling in a hybrid QD-MNP system
摘要： We investigate the electromagnetically induced grating (EIG) in a quantum dot-metal nanoparticle (QD-MNP) hybrid system. The EIG can be controlled and improved by the surface plasmon effect and the interdot tunneling effect between quantum dots. By manipulating the tunneling effect and the QD-MNP distance, not only the first-order diffraction intensity of the grating can be efficiently enhanced, but also the EIG can be switched from the absorption grating to the gain grating. Almost two times of the first-order diffraction efficiencies can be achieved in the gain gratings compared with the absorption gratings.
关键词： electromagnetically induced grating,dot-metal nanoparticle,electromagnetically induced transparency,plasmon-exciton effect,tunneling
更新于2025-09-04 15:30:14
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Electrical Manipulation of Electromagnetically Induced Transparency for Slow Light Purpose Based on Metal-Graphene Hybrid Metamaterial
摘要： A terahertz metamaterial is presented and numerically investigated to achieve tunable electromagnetically induced transparency (EIT) for slow light. The unit cell consists of cut-wire pairs and U-shaped ring resonators with graphene strips placed between the metal film and the SiO2/Si substrate. Through bright-dark mode coupling, the radiative resonance induced by the U-shaped ring is suppressed, and then the typical EIT effect is realized. The transparency window and the accompanied group delay can be electrically manipulated with different Fermi energy of the graphene. By analyzing the surface distribution, the underlying tuning mechanism of this hybrid metamaterial is investigated in detail. Moreover, the transparency peak decreases slightly with the increasing strip width of the graphene layer but completely vanishes as the strip width exceeds the length of the covered U-shaped ring. The influence of the critical index of graphene quality, i.e., carrier mobility on the EIT effect, is considered. The results of this study may provide valuable guidance in designing and analyzing tunable EIT structures based on a metal-graphene hybrid structure for slow light purposes.
关键词： slow light,electromagnetically induced transparency,graphene,metamaterial
更新于2025-09-04 15:30:14