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Showing papers on "Electromagnetically induced transparency published in 2016"


Journal ArticleDOI
30 Jun 2016-Nature
TL;DR: This work realizes the Fock–Darwin Hamiltonian for photons in a magnetic field and harmonic trap, and opens the door to exploration of the interplay of geometry and topology, and in conjunction with Rydberg electromagnetically induced transparency, enables studies of photonic fractional quantum Hall fluids and direct detection of anyons.
Abstract: Synthetic photonic materials are an emerging platform for exploring the interface between microscopic quantum dynamics and macroscopic material properties. Photons experiencing a Lorentz force develop handedness, providing opportunities to study quantum Hall physics and topological quantum science. Here we present an experimental realization of a magnetic field for continuum photons. We trap optical photons in a multimode ring resonator to make a two-dimensional gas of massive bosons, and then employ a non-planar geometry to induce an image rotation on each round-trip. This results in photonic Coriolis/Lorentz and centrifugal forces and so realizes the Fock–Darwin Hamiltonian for photons in a magnetic field and harmonic trap. Using spatial- and energy-resolved spectroscopy, we track the resulting photonic eigenstates as radial trapping is reduced, finally observing a photonic Landau level at degeneracy. To circumvent the challenge of trap instability at the centrifugal limit, we constrain the photons to move on a cone. Spectroscopic probes demonstrate flat space (zero curvature) away from the cone tip. At the cone tip, we observe that spatial curvature increases the local density of states, and we measure fractional state number excess consistent with the Wen–Zee theory, providing an experimental test of this theory of electrons in both a magnetic field and curved space. This work opens the door to exploration of the interplay of geometry and topology, and in conjunction with Rydberg electromagnetically induced transparency, enables studies of photonic fractional quantum Hall fluids and direct detection of anyons.

199 citations


Journal ArticleDOI
TL;DR: By mapping the strong interaction between Rydberg excitations in ultra-cold atomic ensembles onto single photons via electromagnetically induced transparency, it is now possible to realize a medium which exhibits a strong optical nonlinearity at the level of individual photons.
Abstract: By mapping the strong interaction between Rydberg excitations in ultra-cold atomic ensembles onto single photons via electromagnetically induced transparency, it is now possible to realize a medium which exhibits a strong optical nonlinearity at the level of individual photons. We review the theoretical concepts and the experimental state-of-the-art of this exciting new field, and discuss first applications in the field of all-optical quantum information processing.

197 citations


Journal ArticleDOI
TL;DR: In this article, a reconfigurable metamaterial with independently controlled bright and dark mode resonators is proposed for advanced manipulation of the classical analog of EIT and slow light effects in the THz spectral region.
Abstract: 1 wileyonlinelibrary.com C o m m u n iC a io n and their possible applications. The ultimate form of active manipulation of EIT phenomenon will be when all three primary parameters are controlled independently. The independent control of individual resonators demands for the controllability at unit cell level, and conventional approaches such as optical pumping of photoconductive elements or thermally controlled superconductor are restricted to provide only global control. Recently, microelectromechanical systems (MEMS) based tunable metamaterials have been reported to achieve controllability at unit cell level, along with the added advantage of being electrically controlled, miniaturized size and enhanced electrooptic performance. The versatility of MEMS design has enabled active manipulation of numerous THz properties such as magnetic resonance,[19–22] electrical resonance,[23–25] anisotropy,[26] broadband response,[27] isotropic resonance switching[28] multiresonance switching,[29–31] and coupling strength between resonators.[32] The enhanced controllability and direct integration of MEMS actuators into metamaterial unit cell geometry is an ideal fit for the realization of selective control of coupled mode resonators. In this Communication, reconfigurable metamaterial with independently controlled bright and dark mode resonators is proposed for advanced manipulation of the classical analog of EIT and slow light effects in THz spectral region. The active control of bright mode resonator enables modulation of EIT intensity, while the tuning of dark mode resonance causes the EIT peak to tune in frequency. Furthermore, simultaneous switching of bright and dark mode resonators results in dynamic switching of the system between coupled and uncoupled states. The proposed approach of selective reconfiguration can be scaled for multiresonator systems, which can be coupled either through inductive, capacitive, or conductive means. The metamaterial consists of 80 × 80 periodic array of cut wire resonator (CWR) with closely placed split ring resonators (SRRs), as shown in Figure 1 and Figure 2. The periodicity of unit cell is 100 μm along both axial directions. The CWR has length, lC = 60 μm and width, wC = 5 μm, respectively. The SRRs have a base length, bS = 30 μm, side length, lS = 20 μm, and split gap, gS = 4 μm. The SRRs are placed at a distance of S = 2 μm from the CWR. When the polarization of the excitation field is along the CWR arm, the dipole mode resonance of the CWR will be the bright mode and the inductive-capacitive (LC) mode of SRR resonance acts as the dark mode. Thus for the incident THz polarization, the direct excitation of the bright mode induces image charges on the nearby SRRs through nearfield inductive coupling, thereby exciting the LC resonance of the SRRs. These bright-dark resonances have contrasting line widths with identical resonance frequencies and under a strong coupling regime they experience an EIT-type of interference that gives rise to a sharp transmission peak. Thus, through Active Control of Electromagnetically Induced Transparency Analog in Terahertz MEMS Metamaterial

196 citations


Journal ArticleDOI
TL;DR: The results show that the resonant modes cannot only be tuned dramatically by geometrically changing the grating amplitude and the interlayer spacing, but also by dynamically varying the Fermi energy of the graphene sheets.
Abstract: To achieve plasmonically induced transparency (PIT), general near-field plasmonic systems based on couplings between localized plasmon resonances of nanostructures rely heavily on the well-designed interantenna separations. However, the implementation of such devices and techniques encounters great difficulties mainly to due to very small sized dimensions of the nanostructures and gaps between them. Here, we propose and numerically demonstrate that PIT can be achieved by using two graphene layers that are composed of a upper sinusoidally curved layer and a lower planar layer, avoiding any pattern of the graphene sheets. Both the analytical fitting and the Akaike Information Criterion (AIC) method are employed efficiently to distinguish the induced window, which is found to be more likely caused by Autler-Townes splitting (ATS) instead of electromagnetically induced transparency (EIT). Besides, our results show that the resonant modes cannot only be tuned dramatically by geometrically changing the grating amplitude and the interlayer spacing, but also by dynamically varying the Fermi energy of the graphene sheets. Potential applications of the proposed system could be expected on various photonic functional devices, including optical switches, plasmonic sensors.

178 citations


Journal ArticleDOI
TL;DR: A single-photon pulse creates a π phase shift for another light pulse, which is important for optical quantum computation and offers a variety of applications in the field of quantum information processing.
Abstract: A deterministic photon-photon quantum logic gate is a long-standing goal. Building such a gate becomes possible if a light pulse containing only one photon imprints a phase shift of π onto another light field. We experimentally demonstrate the generation of such a π phase shift with a single-photon pulse. A first light pulse containing less than one photon on average is stored in an atomic gas. Rydberg blockade combined with electromagnetically induced transparency creates a phase shift for a second light pulse, which propagates through the medium. We measure the π phase shift of the second pulse when we postselect the data upon the detection of a retrieved photon from the first pulse. This demonstrates a crucial step toward a photon-photon gate and offers a variety of applications in the field of quantum information processing.

171 citations


Journal ArticleDOI
20 Dec 2016
TL;DR: In this article, the authors demonstrate diamond optomechanical crystals (OMCs), a device platform to enable such applications, wherein the co-localization of ∼200 THz photons and few to 10 GHz phonons in a quasi-periodic diamond nanostructure leads to coupling of an optical cavity field to a mechanical mode via radiation pressure.
Abstract: Cavity-optomechanical systems realized in single-crystal diamond are poised to benefit from its extraordinary material properties, including low mechanical dissipation and a wide optical transparency window. Diamond is also rich in optically active defects, such as the nitrogen-vacancy (NV) and silicon-vacancy (SiV) centers, which behave as atom-like systems in the solid state. Predictions and observations of coherent coupling of the NV electronic spin to phonons via lattice strain have motivated the development of diamond nanomechanical devices aimed at the realization of hybrid quantum systems in which phonons provide an interface with diamond spins. In this work, we demonstrate diamond optomechanical crystals (OMCs), a device platform to enable such applications, wherein the co-localization of ∼200 THz photons and few to 10 GHz phonons in a quasi-periodic diamond nanostructure leads to coupling of an optical cavity field to a mechanical mode via radiation pressure. In contrast to other material systems, diamond OMCs operating in the resolved-sideband regime possess large intracavity photon capacities (>10^5) and sufficient optomechanical coupling rates to reach a cooperativity of ∼20 at room temperature, allowing for the observation of optomechanically induced transparency and the realization of large-amplitude optomechanical self-oscillations.

143 citations


Journal ArticleDOI
TL;DR: In this paper, a physically feasible three-level transitionless quantum driving with multiple Schrodinger dynamics (MSDs) is proposed to control accurately population transfer and entanglement generation for three level quantum systems in a nonadiabatic way.
Abstract: Three-level quantum systems, which possess some unique characteristics beyond two-level ones, such as electromagnetically induced transparency, coherent trapping, and Raman scatting, play important roles in solid-state quantum information processing. Here, we introduce an approach to implement the physically feasible three-level transitionless quantum driving with multiple Schr\"odinger dynamics (MSDs). It can be used to control accurately population transfer and entanglement generation for three-level quantum systems in a nonadiabatic way. Moreover, we propose an experimentally realizable hybrid architecture, based on two nitrogen-vacancy-center ensembles coupled to a transmission line resonator, to realize our transitionless scheme which requires fewer physical resources and simple procedures, and it is more robust against environmental noises and control parameter variations than conventional adiabatic passage techniques. All these features inspire the further application of MSDs on robust quantum information processing in experiment.

129 citations


Journal ArticleDOI
TL;DR: By mapping the strong interaction between Rydberg excitations in ultra-cold atomic ensembles onto single photons via electromagnetically induced transparency, it is now possible to realize a nonlinear optical medium which exhibits a strong optical nonlinearity at the level of individual photons as discussed by the authors.
Abstract: By mapping the strong interaction between Rydberg excitations in ultra-cold atomic ensembles onto single photons via electromagnetically induced transparency, it is now possible to realize a nonlinear optical medium which exhibits a strong optical nonlinearity at the level of individual photons. We review the theoretical concepts and the experimental state-of-the-art of this exciting new field, and discuss first applications in the field of all-optical quantum information processing.

129 citations


Journal ArticleDOI
TL;DR: In this article, a single-shot measurement of phonon numbers is used to investigate the EIT cooling in strings of trapped atomic ions and demonstrate simultaneous ground-state cooling of all radial modes in under 1 ms.
Abstract: Electromagnetically-induced-transparency (EIT) cooling is a ground-state cooling technique for trapped particles. EIT offers a broader cooling range in frequency space compared to more established methods. In this work, we experimentally investigate EIT cooling in strings of trapped atomic ions. In strings of up to 18 ions, we demonstrate simultaneous ground-state cooling of all radial modes in under 1 ms. This is a particularly important capability in view of emerging quantum simulation experiments with large numbers of trapped ions. Our analysis of the EIT cooling dynamics is based on a technique enabling single-shot measurements of phonon numbers, by rapid adiabatic passage on a vibrational sideband of a narrow transition.

118 citations


Journal ArticleDOI
TL;DR: In this article, the authors extend quantum sensing via cold atoms and electromagnetically induced transparency to the strong-field regime, which is an essential step toward calibration-free rf electric field sensors for a wide range of applications that include antenna calibration, metamaterial characterization, and subwavelength imaging.
Abstract: Even in this day and age, precise absolute measurement of electric fields is not trivial. The authors extend quantum sensing via cold atoms and electromagnetically induced transparency to the strong-field regime. In this regime, existing techniques are insufficient due to the complex and highly nonlinear response of the atoms. This is an essential step toward calibration-free rf electric-field sensors for a wide range of applications that include antenna calibration, metamaterial characterization, and subwavelength imaging.

114 citations


Journal ArticleDOI
TL;DR: Exciton-plasmon coupling in hybrids of a monolayer transition metal dichalcogenide and Ag nanoparticles is investigated in the weak and strong coupling regimes, evidencing coherent energy exchange between excitons and plasmons.
Abstract: Exciton-plasmon coupling in hybrids of a monolayer transition metal dichalcogenide and Ag nanoparticles is investigated in the weak and strong coupling regimes. In the weak coupling regime, both absorption enhancement and the Purcell effect collectively modify the photoluminescence properties of the semiconductor. In the strong coupling regime, electromagnetically induced transparency dips are displayed, evidencing coherent energy exchange between excitons and plasmons.

Journal ArticleDOI
TL;DR: In this paper, an approach for improved sensitivity in weak radio frequency (RF) electric-field strength measurements using Rydberg electromagnetically induced transparency (EIT) in an atomic vapor is presented.
Abstract: In this work, we demonstrate an approach for improved sensitivity in weak radio frequency (RF) electric-field strength measurements using Rydberg electromagnetically induced transparency (EIT) in an atomic vapor. This is accomplished by varying the RF frequency around a resonant atomic transition and extrapolating the weak on-resonant field strength from the resulting off-resonant Autler-Townes (AT) splittings. This measurement remains directly traceable to SI compared to previous techniques, precluding any knowledge of experimental parameters such as optical beam powers as is the case when using the curvature of the EIT line shape to measure weak fields. We use this approach to measure weak RF fields at 182 GHz and 208 GHz demonstrating improvement greater than a factor of 2 in the measurement sensitivity compared to on-resonant AT splitting RF electric field measurements.

Journal ArticleDOI
TL;DR: In this paper, a three-particle interaction between one magnon and two photons whose frequency difference is resonant with the magnon frequency was proposed to achieve coherent conversion of photons to magnons, and back, providing a natural mechanism for rapid control of interactions between stationary spins with long coherence times and high speed photons.
Abstract: Coherent conversion of photons to magnons, and back, provides a natural mechanism for rapid control of interactions between stationary spins with long coherence times and high-speed photons. Despite the large frequency difference between optical photons and magnons, coherent conversion can be achieved through a three-particle interaction between one magnon and two photons whose frequency difference is resonant with the magnon frequency, as in optomechanics with two photons and a phonon. The large spin density of a transparent ferromagnetic insulator (such as the ferrite yttrium iron garnet) in an optical cavity provides an intrinsic photon-magnon coupling strength that we calculate to exceed reported optomechanical couplings. A large cavity photon number and properly selected cavity detuning produce a predicted effective coupling strength sufficient for observing electromagnetically induced transparency and the Purcell effect, and even to reach the ultrastrong coupling regime.

Journal ArticleDOI
TL;DR: A frequency tunable EIT analogue in the terahertz regime by integrating photoactive silicon into the metamaterial unit cell is presented, delivering frequency agility of the EIT resonance and may enable novel ultrafast tunable devices for integrated plasmonic circuits.
Abstract: Recently reported active metamaterial analogues of electromagnetically induced transparency (EIT) are promising in developing novel optical components, such as active slow light devices. However, most of the previous works have focused on manipulating the EIT resonance strength at a fixed characteristic frequency and, therefore, realized on-to-off switching responses. To further extend the functionalities of the EIT effect, here we present a frequency tunable EIT analogue in the terahertz regime by integrating photoactive silicon into the metamaterial unit cell. A tuning range from 0.82 to 0.74 THz for the EIT resonance frequency is experimentally observed by optical pump-terahertz probe measurements, allowing a frequency tunable group delay of the terahertz pulses. This straightforward approach delivers frequency agility of the EIT resonance and may enable novel ultrafast tunable devices for integrated plasmonic circuits.

Journal ArticleDOI
TL;DR: Analyzing the driven dissipative dynamics of the atomic gas, it is shown that the interplay between coherent light coupling, radiative decay, and strong Rydberg-Rydberg atom interactions leads to the emergence of sizable effective interactions while providing remarkably long coherence times.
Abstract: We develop an approach to generate finite-range atomic interactions via optical Rydberg-state excitation and study the underlying excitation dynamics in theory and experiment. In contrast to previous work, the proposed scheme is based on resonant optical driving and the establishment of a dark state under conditions of electromagnetically induced transparency (EIT). Analyzing the driven dissipative dynamics of the atomic gas, we show that the interplay between coherent light coupling, radiative decay, and strong Rydberg-Rydberg atom interactions leads to the emergence of sizable effective interactions while providing remarkably long coherence times. The latter are studied experimentally in a cold gas of strontium atoms for which the proposed scheme is most efficient. Our measured atom loss is in agreement with the theoretical prediction based on binary effective interactions between the driven atoms.

Journal ArticleDOI
TL;DR: In this paper, the combined qubit-cavity states of a superconducting transmon qubit in a three-dimensional copper cavity with two microwave drives are established, two legs of which are defined by a dipole transition and a two-photon transition.
Abstract: Atomic three-level systems dressed by two coherent electromagnetic fields can exhibit coherent population trapping and electromagnetically induced transparency (EIT) due to quantum interference. By addressing the combined qubit-cavity states of a superconducting transmon qubit in a three-dimensional copper cavity with two microwave drives we establish an effective system, two legs of which are defined by a dipole transition and a two-photon transition. This circuit-based system allows the observation of three-microwave-photon Raman coherence effects, including coherent population trapping and EIT, which are demonstrated here with both steady-state spectroscopic techniques and time-domain measurements. By sending Gaussian microwave pulses through the cavity in the EIT regime, a negative group velocity of the pulse is observed with the peak of the pulse exiting the cavity 9.4 μs before entering.

Journal ArticleDOI
TL;DR: Extended systematic measurements of the storage efficiency versus optical depth, control Rabi frequency, and probe pulse duration confirm the theoretically expected behavior of an EIT-driven solid-state memory.
Abstract: We demonstrate efficient storage and retrieval of light pulses by electromagnetically induced transparency (EIT) in a Pr^{3+}:Y_{2}SiO_{5} crystal. Using a ring-type multipass configuration, we increase the optical depth (OD) of the medium up to a factor of 16 towards OD≈96. Combining the large optical depth with optimized conditions for EIT, we reach a light storage efficiency of (76.3±3.5)%. In addition, we perform extended systematic measurements of the storage efficiency versus optical depth, control Rabi frequency, and probe pulse duration. The data confirm the theoretically expected behavior of an EIT-driven solid-state memory.

Journal ArticleDOI
TL;DR: In this paper, the authors demonstrate hybridization of optical cavity photons with atomic Rydberg excitations using electromagnetically induced transparency (EIT) and identify the generalized EIT linewidth for optical cavities.
Abstract: We demonstrate hybridization of optical cavity photons with atomic Rydberg excitations using electromagnetically induced transparency (EIT). The resulting dark state Rydberg polaritons exhibit a compressed frequency spectrum and enhanced lifetime indicating strong light-matter mixing. We study the coherence properties of cavity Rydberg polaritons and identify the generalized EIT linewidth for optical cavities. Strong collective coupling suppresses polariton losses due to inhomogeneous broadening, which we demonstrate by using different Rydberg levels with a range of polarizabilities. Our results point the way towards using cavity Rydberg polaritons as a platform for creating photonic quantum materials.

Journal ArticleDOI
TL;DR: This work demonstrates a new mechanism of optically induced transparency in a micro-cavity by introducing a four-wave mixing gain to nonlinearly couple two separated resonances of the micro-Cavity in an ambient environment and shows that the unidirectional gain of the four- wave mixing can lead to the remarkable effect of non-reciprocal transmission at the transparency windows.
Abstract: Electromagnetically induced transparency has the unique ability to optically control transparency windows with low light in atomic systems. However, its practical applications in quantum physics and information science are limited due to rigid experimental requirements. Here we demonstrate a new mechanism of optically induced transparency in a micro-cavity by introducing a four-wave mixing gain to nonlinearly couple two separated resonances of the micro-cavity in an ambient environment. A signature Fano-like resonance was observed owing to the nonlinear interference of the two coupled resonances. Moreover, we show that the unidirectional gain of the four-wave mixing can lead to the remarkable effect of non-reciprocal transmission at the transparency windows. Optically induced transparency may offer a unique platform for a compact, integrated solution to all-optical and quantum information.

Book ChapterDOI
TL;DR: In this article, the authors present an overview of this rapidly developing field, from classical effects to quantum manifestations of the nonlocal nonlinearities emerging in such systems, describing the many experimental breakthroughs so far demonstrated and discuss potential applications looming on the horizon.
Abstract: Coupling light to ensembles of strongly interacting particles has emerged as a promising route toward achieving few photon nonlinearities. One specific way to implement this kind of nonlinearity is to interface light with highly excited atomic Rydberg states by means of electromagnetically induced transparency, an approach which allows freely propagating photons to acquire synthetic interactions of hitherto unprecedented strength. Here, we present an overview of this rapidly developing field, from classical effects to quantum manifestations of the nonlocal nonlinearities emerging in such systems. With an emphasis on underlying theoretical concepts, we describe the many experimental breakthroughs so far demonstrated and discuss potential applications looming on the horizon.

Journal ArticleDOI
20 Jul 2016
TL;DR: In this paper, the authors predict the possibility of highly nonlocal optical nonlinearities for light propagating in atomic media trapped near a nano-waveguide, where long-range interactions between the atoms can be tailored.
Abstract: Nonlinear optical phenomena are typically local. Here, we predict the possibility of highly nonlocal optical nonlinearities for light propagating in atomic media trapped near a nano-waveguide, where long-range interactions between the atoms can be tailored. When the atoms are in an electromagnetically induced transparency configuration, the atomic interactions are translated to long-range interactions between photons and thus to highly nonlocal optical nonlinearities. We derive and analyze the governing nonlinear propagation equation, finding a roton-like excitation spectrum for light and the emergence of order in its output intensity. These predictions open the door to studies of unexplored wave dynamics and many-body physics with highly nonlocal interactions of optical fields in one dimension.

Journal ArticleDOI
TL;DR: This work shows that the dark mode coupling mechanism of the classical EIT effect enables an exotic and straightforward excitation of SPs in a metasurface system, and manifest the potential of developing plasmonic metadevices with unique functionalities.
Abstract: Control over surface plasmons (SPs) is essential in a variety of cutting-edge applications, such as highly integrated photonic signal processing systems, deep-subwavelength lasing, high-resolution imaging, and ultrasensitive biomedical detection. Recently, asymmetric excitation of SPs has attracted enormous interest. In free space, the analog of electromagnetically induced transparency (EIT) in metamaterials has been widely investigated to uniquely manipulate the electromagnetic waves. In the near field, we show that the dark mode coupling mechanism of the classical EIT effect enables an exotic and straightforward excitation of SPs in a metasurface system. This leads to not only resonant excitation of asymmetric SPs but also controllable exotic SP focusing by the use of the Huygens-Fresnel principle. Our experimental findings manifest the potential of developing plasmonic metadevices with unique functionalities.

Journal ArticleDOI
TL;DR: This paper proposes a design of the metamaterial based on Si nanoresonators that can support an EIT-like resonant response and optically tune the response by hybridizing them with a layer of a phase change material.
Abstract: Electromagnetically induced transparency (EIT) is a pump-induced narrowband transparency window within an absorption line of the probe beam spectrum in an atomic system. In this paper we propose a way to bring together the all-dielectric metamaterials to have EIT-like effects and to optically tune the response by hybridizing them with a layer of a phase change material. We propose a design of the metamaterial based on Si nanoresonators that can support an EIT-like resonant response. On the top of the resonators we consider a thin layer of a chalcogenide phase change material, which we will use to tune the optical response. Our choice is Ge2Sb2Te5 (GST), since it has two stable phases at room temperature, namely amorphous and crystalline, between which it can be switched quickly, nonvolatively and reversibly, sustaining a large number of switching cycles. They differ in optical properties, while still having moderately low losses in telecom range. Since such dielectric resonators do not have non-radiative losses of metals around 1550nm, they can lead to a high-Q factor of the EIT-like response in this range. Firstly, we optimize the starting structure so that it gives an EIT-like response at 1550 nm when the GST layer is in the amorphous state. Our starting design uses glass as a substrate, but we also consider implementation in SOI technology. If we then switch the thin layer of GST to its crystalline phase, which has higher losses, the EIT-like response is red shifted, providing around 10:1 contrast at 1550nm. This reversible tuning can be done with an ns visible pulsed laser. We discuss the results of the simulation of the dielectric metasurface for different configurations and the tuning possibility.

Journal ArticleDOI
TL;DR: In this article, a three-dimensionsal toroidal metamaterial where two different toroidal dipoles along orthogonal directions have been observed has been experimentally and numerically demonstrated, where the intriguing properties of the toroidal resonances may open up avenues for applications in toroidal moments generator, sensing and slow light devices.
Abstract: Toroidal multipoles have recently been explored in various scientific communities, ranging from atomic and molecular physics, electrodynamics, and solid-state physics to biology. Here we experimentally and numerically demonstrate a three-dimensionsal toroidal metamaterial where two different toroidal dipoles along orthogonal directions have been observed. The chosen toroidal metamaterial also simultaneously supports Fano resonance and the classical analog of electromagnetically induced transparency (EIT) phenomena in the transmission spectra that originate from the electric–toroidal dipole and electric–magnetic dipole destructive interference. The intriguing properties of the toroidal resonances may open up avenues for applications in toroidal moments generator, sensing and slow-light devices.

Journal ArticleDOI
TL;DR: In this paper, a spectral analysis of Rydberg atoms in strong microwave fields using electromagnetically induced transparency (EIT) as an all-optical readout is presented.
Abstract: We present a spectral analysis of Rydberg atoms in strong microwave fields using electromagnetically induced transparency (EIT) as an all-optical readout. The measured spectroscopic response enables optical, atom-based electric field measurements of high-power microwaves. In our experiments, microwaves are irradiated into a room-temperature rubidium vapor cell. The microwaves are tuned near the two-photon 65D-66D Rydberg transition and reach an electric field strength of 230V/m, about 20% of the microwave ionization threshold of these atoms. A Floquet treatment is used to model the Rydberg level energies and their excitation rates. We arrive at an empirical model for the field-strength distribution inside the spectroscopic cell that yields excellent overall agreement between the measured and calculated Rydberg EIT-Floquet spectra. Using spectral features in the Floquet maps we achieve an absolute strong-field measurement precision of 6%.

Journal ArticleDOI
TL;DR: In this article, a broadband absorber composed of graphene analog of electromagnetically induced transparency (EIT) and a metal ground plane spaced by a thin SiO 2 dielectric layer is proposed and investigated.
Abstract: A broadband absorber, which is composed of graphene analog of electromagnetically induced transparency (EIT) and a metal ground plane spaced by a thin SiO 2 dielectric layer, is proposed and investigated. Numerical results reveal that the working bandwidth can be dynamically tuned between broadband absorption and narrowband absorption by varying the Fermi level of graphene through controlling of the electrostatic gating. Furthermore, absorption behaviors can be tuned to the state of off when the electric polarized is rotated to another axis. It is also found that the coupling strength between the radiative element and dark element is tuned by the distance between the disconnected vertical graphene strip and horizontal graphene strip. In addition, this type of graphene-based absorber is very sensitive to the incident angles.

Journal ArticleDOI
TL;DR: It is found that the fifth-order nonlinear optical susceptibility in the Rydberg-EIT system may be five orders of magnitude larger than that obtained in traditional EIT systems.
Abstract: We investigate the optical Kerr nonlinearities of an ensemble of cold Rydberg atoms under the condition of electromagnetically induced transparency (EIT). By using an approach beyond mean-field theory, we show that the system possesses not only enhanced third-order nonlinear optical susceptibility, but also giant fifth-order nonlinear optical susceptibility, which has a cubic dependence on atomic density. Our results demonstrate that both the third-order and the fifth-order nonlinear optical susceptibilities consist of two parts, contributed respectively by photon-atom interaction and Rydberg-Rydberg interaction. The Kerr nonlinearity induced by the Rydberg-Rydberg interaction plays a leading role at high atomic density. We find that the fifth-order nonlinear optical susceptibility in the Rydberg-EIT system may be five orders of magnitude larger than that obtained in traditional EIT systems. The results obtained may have promising applications in light and quantum information processing and transmission at weak-light level.

Journal ArticleDOI
TL;DR: In this paper, the authors reported experimental results of the active switching of electromagnetically induced transparency (EIT) analogue by controlling the dark mode excitation pathways in a microelectromechanical system based tri-atomic metamolecule, operating in the terahertz spectral region.
Abstract: We report experimental results of the active switching of electromagnetically induced transparency (EIT) analogue by controlling the dark mode excitation pathways in a microelectromechanical system based tri-atomic metamolecule, operating in the terahertz spectral region. The tri-atomic metamolecule consists of two bright cut wire resonators (CWRs) on either side of the dark split ring resonators (SRRs). Each of the CWRs can independently excite the dark inductive-capacitive resonance mode of the SRRs through inductive coupling, and this allows for the dual pathways of dark mode excitation. The CWRs are made movable along the out-of-plane direction and electrically isolated to achieve selective reconfiguration. Hence, by controlling the physical position of these CWRs, the excitation pathways can be actively reconfigured. This enables the strong excitation of EIT analogue at 0.65 THz, only when one of the pathways is made accessible. Moreover, the transparency peak is completely modulated when both pathwa...

Journal ArticleDOI
TL;DR: In this paper, simultaneous electromagnetically-induced transparency (EIT) with cesium (Cs) and rubidium (Rb) Rydberg atoms in the same vapor cell with coincident (overlapping) optical fields was demonstrated.
Abstract: We demonstrate simultaneous electromagnetically-induced transparency (EIT) with cesium (Cs) and rubidium (Rb) Rydberg atoms in the same vapor cell with coincident (overlapping) optical fields. Each atomic system can detect radio frequency (RF) electric (E) field strengths through the modification of the EIT signal (Autler-Townes (AT) splitting), which leads to a direct International System of Unit traceable RF E-field measurement. We show that these two systems can detect the same RF E-field strength simultaneously, which provides a direct in situ comparison of Rb and Cs RF measurements in Rydberg atoms. In effect, this allows us to perform two measurements of the same E-field strength, providing a relative comparison of the dipole moments of the two atomic species. This gives two measurements that help rule out systematic effects and uncertainties in this E-field metrology approach, which are important when establishing an international measurement standard for an E-field strength, and is a necessary step for this method to be accepted as a standard calibration technique. We use this approach to measure E-fields at 9.2 GHz, 11.6 GHz, and 13.4 GHz, which correspond to three different atomic states (different principal atomic numbers and angular momentums) for the two atom species.

Journal ArticleDOI
TL;DR: The 3-D split-ring resonators allow new schemes to observe single and multi-band classical analogues of electromagnetically induced transparencies that has huge potential applications in slowing down light, sensing modalities, and filtering functionalities either in the passive mode or the active mode where such effects could be tuned by integrating materials with dynamic properties.
Abstract: Metamaterials have recently enabled coupling induced transparency due to interference effects in coupled subwavelength resonators. In this work, we present a three dimensional (3-D) metamaterial design with six-fold rotational symmetry that shows electromagnetically induced transparency with a strong polarization dependence to the incident electromagnetic wave due to the ultra-sharp resonance line width as a result of interaction between the constituent meta-atoms. However, when the six-fold rotationally symmetric unit cell design was re-arranged into a fourfold rotational symmetry, we observed the excitation of a polarization insensitive dual-band transparency. Thus, the 3-D split-ring resonators allow new schemes to observe single and multi-band classical analogues of electromagnetically induced transparencies that has huge potential applications in slowing down light, sensing modalities, and filtering functionalities either in the passive mode or the active mode where such effects could be tuned by integrating materials with dynamic properties.