Showing papers on "Electromagnetically induced transparency published in 2004"
TL;DR: If all-optical devices using photonic crystal designs promise to be smaller than the wavelength of light, and to operate with bandwidths that are very difficult to achieve electronically, operation at single-photon power levels could be feasible.
Abstract: The quest for all-optical signal processing is generally deemed to be impractical because optical nonlinearities are usually weak. The emerging field of nonlinear photonic crystals seems destined to change this view dramatically. Theoretical considerations show that all-optical devices using photonic crystal designs promise to be smaller than the wavelength of light, and to operate with bandwidths that are very difficult to achieve electronically. When created in commonly used materials, these devices could operate at powers of only a few milliwatts. Moreover, if these designs are combined with materials and systems that support electromagnetically induced transparency, operation at single-photon power levels could be feasible.
776 citations
TL;DR: A new all-optical mechanism that can compress the bandwidth of light pulses to absolute zero, and bring them to a complete stop, is introduced and demonstrated by finite-difference time-domain simulations of an implementation in photonic crystals.
Abstract: We introduce a new all-optical mechanism that can compress the bandwidth of light pulses to absolute zero, and bring them to a complete stop. The mechanism can be realized in a system consisting of a waveguide side coupled to tunable resonators, which generates a photonic band structure that represents a classical analogue of the electromagnetically induced transparency. The same system can also achieve a time-reversal operation. We demonstrate the operation of such a system by finite-difference time-domain simulations of an implementation in photonic crystals.
433 citations
TL;DR: In this article, the authors demonstrate slow light via population oscillation in semiconductor quantum-well structures for the first time and infer group velocity as low as 9600 m/s from the experimentally measured dispersive characteristics.
Abstract: We demonstrate slow light via population oscillation in semiconductor quantum-well structures for the first time. A group velocity as low as 9600 m/s is inferred from the experimentally measured dispersive characteristics. The transparency window exhibits a bandwidth as large as 2 GHz.
264 citations
TL;DR: A parallel configuration of two interacting whispering-gallery-mode optical resonators is theoretically studied and a narrowband modal structure is shown as a basis for a widely tunable delay line.
Abstract: We theoretically study a parallel configuration of two interacting whispering-gallery-mode optical resonators and show a narrowband modal structure as a basis for a widely tunable delay line. For the optimum coupling configuration the system can possess an unusually narrow spectral feature with a much narrower bandwidth than the loaded bandwidth of each individual resonator. The effect has a direct analogy with the phenomenon of electromagnetically induced transparency in quantum systems for which the interference of spontaneous emission results in ultranarrow resonances.
229 citations
TL;DR: This work shows the formation of ultraslow bright and dark optical solitons in a lifetime-broadened three-state atomic system under Raman excitation and discusses why such ultraslow optical solites may not exist under the conditions of the usual electromagnetically induced transparency configuration.
Abstract: We show the formation of ultraslow bright and dark optical solitons in a lifetime-broadened three-state atomic system under Raman excitation. We also discuss why such ultraslow optical solitons may not exist under the conditions of the usual electromagnetically induced transparency configuration where zero one- and two-photon detunings are required.
212 citations
Book•
30 Nov 2004TL;DR: In this article, the authors focus on how refractive index can vary with frequency in such a way that the group velocities of optical pulses can be much greater or much smaller than the speed of light in vacuum.
Abstract: The propagation of light in dispersive media is a subject of fundamental as well as practical importance. In recent years attention has focused in particular on how refractive index can vary with frequency in such a way that the group velocities of optical pulses can be much greater or much smaller than the speed of light in vacuum, or in which the refractive index can be negative. Treating these topics at an introductory to intermediate level, Fast Light, Slow Light and Left-Handed Light focuses on the basic theory and describes the significant experimental progress made during the past decade. The book pays considerable attention to the fact that superluminal group velocities are not in conflict with special relativity and to the role of quantum effects in preventing superluminal communication and violations of Einstein causality. It also explores some of the basic physics at the opposite extreme of very slow group velocities as well as stopped and regenerated light, including the concepts of electromagnetically induced transparency and dark-state polaritons. Another very active aspect of the subject discussed concerns the possibility of designing metamaterials in which the refractive index can be negative and propagating light is left-handed in the sense that the phase and group velocities are in opposite directions. The last two chapters are an introduction to some of the basic theory and consequences of negative refractive index, with emphasis on the seminal work carried out since 2000. The possibility that "perfect" lenses can be made from negative-index metamaterials-which has been perhaps the most controversial aspect of the field-is introduced and discussed in some detail.
195 citations
TL;DR: The first experimental demonstration of four-wave mixing using electromagnetically induced transparency in cold atoms is reported, achieving backward-wave, phase-matched difference-frequency conversion at optical powers of a few nanowatts and energies of less than a picojoule.
Abstract: We report the first experimental demonstration of four-wave mixing using electromagnetically induced transparency in cold atoms Backward-wave, phase-matched difference-frequency conversion is achieved at optical powers of a few nanowatts and at energies of less than a picojoule
187 citations
TL;DR: In this paper, the interaction of a weak probe field, having two orthogonally polarized components, with an optically dense medium of four-level atoms in a tripod configuration was studied.
Abstract: We study the interaction of a weak probe field, having two orthogonally polarized components, with an optically dense medium of four-level atoms in a tripod configuration. In the presence of a coherent driving laser, electromagnetically induced transparency is attained in the medium, dramatically enhancing its linear as well as nonlinear dispersion while simultaneously suppressing the probe field absorption. We present the semiclassical and fully quantum analysis of the system. We propose an experimentally feasible setup that can induce large Faraday rotation of the probe field polarization and therefore be used for ultrasensitive optical magnetometry. We then study the Kerr nonlinear coupling between the two components of the probe, demonstrating a novel regime of symmetric, extremely efficient cross-phase modulation, capable of fully entangling two single-photon pulses. This scheme may thus pave the way to photon-based quantum information applications, such as deterministic all-optical quantum computation, dense coding, and teleportation.
157 citations
TL;DR: An experimental study of resonant six-wave mixing in coherently prepared Rb atoms finds that electromagnetically induced transparency in a four-level atomic system suppresses the linear susceptibility and enhances the nonlinear susceptibilities, which leads to the resonantly enhanced, slow-photon six- wave mixing at low light intensities.
Abstract: We report an experimental study of resonant six-wave mixing in coherently prepared Rb atoms. Electromagnetically induced transparency in a four-level atomic system suppresses the linear susceptibility and enhances the nonlinear susceptibilities, which leads to the resonantly enhanced, slow-photon six-wave mixing at low light intensities. The light emission in the six-wave mixing process can be viewed as resulting from diffraction of slow light off a resonant nonlinear grating induced in the four-level system by a standing-wave pump field.
128 citations
TL;DR: In this article, three-level atom optics is introduced as a simple, efficient, and robust method to coherently manipulate and transport neutral atoms in optical micro-trap arrays, and it is shown that under realistic parameters the coherent manipulation and transfer of neutral atoms among dipole traps could be realized in the millisecond range.
Abstract: Three-level atom optics is introduced as a simple, efficient, and robust method to coherently manipulate and transport neutral atoms. The tunneling interaction among three trapped states allows us to realize the spatial analog of the stimulated Raman adiabatic passage, coherent population trapping, and electromagnetically induced transparency techniques and offers a wide range of possible applications. We investigate an implementation in optical microtrap arrays and show that under realistic parameters the coherent manipulation and transfer of neutral atoms among dipole traps could be realized in the millisecond range.
114 citations
TL;DR: In this paper, a variable semiconductor optical buffer based on the electromagnetically induced transparency in a quantum dot waveguide is theoretically investigated with feasible parameters for applications to a 40 Gbps optical network.
Abstract: A variable semiconductor optical buffer based on the electromagnetically induced transparency in a quantum dot waveguide is theoretically investigated with feasible parameters for applications to a 40 Gbps optical network. We show the refractive index and absorption spectra of the quantum dot waveguide at various pump levels, which exhibit an optimal pump power for maximum slow-down factor, in agreement with the previous experimental observation using a Pr-doped solid. The group velocity slow-down factor is theoretically analysed as a function of the pump intensity at different broadened linewidths. Inhomogeneous broadening in self-assembled quantum dots degrades the slow-down factor. In order to reduce the inhomogeneous broadening effects, we propose to use a resonant microcavity structure with quantum dots embedded in the active layer to enhance the slow-down factor.
TL;DR: In this article, a method for generating pulses of light with controllable photon numbers, propagation direction, timing, and pulse shapes is described based on preparation of an atomic ensemble in a state with a desired number of atomic spin excitations, which is later converted into a photon pulse.
Abstract: We describe proof-of-principle experiments demonstrating a novel approach for generating pulses of light with controllable photon numbers, propagation direction, timing, and pulse shapes. The approach is based on preparation of an atomic ensemble in a state with a desired number of atomic spin excitations, which is later converted into a photon pulse. Spatiotemporal control over the pulses is obtained by exploiting long-lived coherent memory for photon states and Electromagnetically Induced Transparency in an optically dense atomic medium. Using photon counting experiments, we observe Electromagnetically Induced Transparency based generation and shaping of few-photon sub-Poissonian light pulses.
TL;DR: The results reported here are the first realization of EIT in the full quantum regime and within the transparency window caused by the electromagnetically induced transparency.
Abstract: The squeezed vacuum resonant on the $^{87}\mathrm{Rb}$ ${D}_{1}$ line (probe light) was injected into an optically dense rubidium gas cell with a coherent light (control light) The output probe light maintained its quadrature squeezing within the transparency window caused by the electromagnetically induced transparency (EIT) The results reported here are the first realization of EIT in the full quantum regime
TL;DR: In this article, a quasiperfect quantum-state transfer between an atomic ensemble and fields in an optical cavity can be achieved in electromagnetically induced transparency (EIT), where a squeezed vacuum field state can be mapped onto the long-lived atomic spin associated to the ground state sublevels of the $\ensuremath{\Lambda}$-type atoms considered.
Abstract: We show that a quasiperfect quantum-state transfer between an atomic ensemble and fields in an optical cavity can be achieved in electromagnetically induced transparency (EIT). A squeezed vacuum field state can be mapped onto the long-lived atomic spin associated to the ground-state sublevels of the $\ensuremath{\Lambda}$-type atoms considered. The EIT on-resonance situation show interesting similarities with the Raman off-resonant configuration. We then show how to transfer the atomic squeezing back to the field exiting the cavity, thus realizing a quantum memory--type operation.
TL;DR: In this article, a three-level V-type atomic system with the ground state coupled by a laser field to only one of the excited states, and with the two excited states coupled together by a dc field was considered.
Abstract: We consider a three-level V-type atomic system with the ground state coupled by a laser field to only one of the excited states, and with the two excited states coupled together by a dc field. Although the dipole moments of the two dipole-allowed transitions are assumed perpendicular, we demonstrate that this system emulates to a large degree a three-level system with parallel dipole moments-the latter being a system that exhibits quantum interference and displays a number of interesting features. As examples, we show that the system can produce extremely large values for the intensity-intensity correlation function, and that its resonance fluorescence spectrum can display ultranarrow lines. The dressed states for this system are identified, and the spectral features are interpreted in terms of transitions among these dressed states. We also show that this system is capable of exhibiting considerable squeezing.
TL;DR: It is discussed how a superconductive analog to electromagnetically induced transparency can be used to establish macroscopic coherence in such systems and, thereby, be utilized as a sensitive probe of decoherence.
Abstract: Superconductive quantum circuits comprise quantized energy levels that may be coupled via microwave electromagnetic fields. Described in this way, one may draw a close analogy to atoms with internal (electronic) levels coupled by laser light fields. In this Letter, we present a superconductive analog to electromagnetically induced transparency that utilizes superconductive quantum circuit designs of present day experimental consideration. We discuss how a superconductive analog to electromagnetically induced transparency can be used to establish macroscopic coherence in such systems and, thereby, be utilized as a sensitive probe of decoherence.
TL;DR: In this article, the authors report experimental studies of electromagnetically induced transparency arising from exciton spin coherence in the transient optical response of GaAs quantum wells, which is a direct result of Coulomb correlations between excitons with opposite spins.
Abstract: We report experimental studies of electromagnetically induced transparency (EIT) arising from exciton spin coherence in the transient optical response of GaAs quantum wells. The exciton spin coherence, which is a direct result of Coulomb correlations between excitons with opposite spins, is induced via bound or unbound two-exciton states. Theoretical analyses based on a three-level model illustrate the manifestation of EIT in a transient regime and provide qualitative guidance for understanding the transient behaviors observed in the EIT experiments. Additional studies of the effects of exciton energy renormalization on optical Stark splitting also provide insights on how exciton many-body interactions can lead to unusual time-dependent asymmetric EIT line shapes.
TL;DR: In this paper, the authors reported an experimental observation of resonant four-wave mixing in cold Rb atoms, which is a type of slow-light four wave mixing at low light intensities.
Abstract: Electromagnetically induced transparency in a four-level atomic system suppresses the linear susceptibility and enhances the nonlinear susceptibilities, which leads to the resonantly enhanced slow-light four-wave mixing at low light intensities. We report an experimental observation of such resonant four-wave mixing in cold Rb atoms.
TL;DR: In this article, the ultranarrow spectral line is confined between two closely spaced electromagnetically induced transparency windows in a nearly degenerate tripod atomic system formed by an ${F}_{g}=1\ensuremath{\rightarrow}{F}{e}=0$ transition, split by a magnetic field.
Abstract: A method is presented for obtaining sub-Doppler and subnatural narrowing and increased absorption of a spectral line. The ultranarrow spectral line is confined between two closely spaced electromagnetically induced transparency windows in a nearly degenerate tripod atomic system formed by an ${F}_{g}=1\ensuremath{\rightarrow}{F}_{e}=0$ transition, split by a magnetic field. The system is driven by a $\ensuremath{\sigma}$-polarized pump and probed by a tunable $\ensuremath{\pi}$-polarized laser. It can be used to measure small magnetic fields and also as a magneto-optic switch.
TL;DR: In this article, the effects of the vacuum-induced coherence on the electromagnetically induced transparency against single and two-photon absorption in the atomic system were investigated. And the authors found that the vacuum induced coherence can lead to probe gain without incoherent pumping.
Abstract: When a four-level Y-type atom with two highest nearly degenerate lying levels interacts with the same vacuum radiation field, its excited levels have vacuum-induced coherence due to the quantum interference between the spontaneous decay channels. We consider the effects of the vacuum-induced coherence on the electromagnetically induced transparency against single- and two-photon absorption in the atomic system. We find that the vacuum-induced coherence can lead to probe gain without incoherent pumping. On the other hand, the coherence can suppress the two-photon transparency, even in some cases where it can enhance the two-photon absorption. Another important result is the finding of the crucial role played by the relative phase between the probe and coupling fields: the two-photon transparency and the probe gain spectra can be modulated by this phase.
TL;DR: In this article, the group velocity of a light pulse propagating through a four-level system exhibiting electromagnetically induced transparency can be manipulated by a pump laser, which induces the large optical nonlinearities with steep normal or anomalous dispersion.
Abstract: The group velocity of a light pulse propagating through a four-level system exhibiting electromagnetically induced transparency can be manipulated by a pump laser. The pump laser induces the large optical nonlinearities with steep normal or anomalous dispersion. We present experimental measurements that demonstrate both slow and superluminal light propagation in cold Rb atoms.
TL;DR: In this article, the authors provide a broad outline of the requirements that should be met by components produced for a QIT industry, and identify electromagnetically induced transparency (EIT) as potentially key enabling science toward the goal of providing widely available few-qubit quantum information processing within the next decade.
Abstract: We provide a broad outline of the requirements that should be met by components produced for a Quantum Information Technology (QIT) industry, and we identify electromagnetically induced transparency (EIT) as potentially key enabling science toward the goal of providing widely available few-qubit quantum information processing within the next decade. As a concrete example, we build on earlier work and discuss the implementation of a two-photon controlled phase gate (and, briefly, a one-photon phase gate) using the approximate Kerr nonlinearity provided by EIT. In this paper, we rigorously analyze the dependence of the performance of these gates on atomic dephasing and field detuning and intensity, and we calculate the optimum parameters needed to apply a π phase shift in a gate of a given fidelity. Although high-fidelity gate operation will be difficult to achieve with realistic system dephasing rates, the moderate fidelities that we believe will be needed for few-qubit QIT seem much more obtainable.
01 May 2004
TL;DR: In this paper, the authors reported an experimental observation of resonant four-wave mixing in cold Rb atoms, which is a type of slow-light four wave mixing at low light intensities.
Abstract: Electromagnetically induced transparency in a four-level atomic system suppresses the linear susceptibility and enhances the nonlinear susceptibilities, which leads to the resonantly enhanced slow-light four-wave mixing at low light intensities. We report an experimental observation of such resonant four-wave mixing in cold Rb atoms.
TL;DR: In this paper, a narrow, isolated, two-photon absorption resonance in 87Rb was observed in the presence of a buffer gas, which is the first time that the EIT resonance has been observed for a large one-poton detuning.
Abstract: We observe a narrow, isolated, two-photon absorption resonance in 87Rb for large one-photon detuning in the presence of a buffer gas. In the absence of a buffer gas, a standard Λ configuration of two laser frequencies gives rise to electromagnetically induced transparency (EIT) for all values of one-photon detuning throughout the inhomogeneously (Doppler) broadened line. However, when a buffer gas is added and the one-photon detuning is comparable to or greater than the Doppler width, an absorption resonance appears instead of the usual EIT resonance. We also observe a large negative group delay (≈−300 μs for a Gaussian pulse that propagates through the media with respect to a reference pulse not affected by the media), corresponding to a superluminal group velocity vg=−c/(3.6×106)=−84 m/s.
17 Jun 2004
TL;DR: In this paper, the authors proposed a compact variable all-optical buffer using slow-light in semiconductor nanostructures, which is achieved by slowing down the optical signal using an external control light source to vary the dispersion characteristic of the medium via electromagnetically induced transparency effect.
Abstract: We proposed a compact variable all-optical buffer using slow-light in semiconductor nanostructures. We discuss the general design principle via dispersion engineering. The buffering effect is achieved by slowing down the optical signal using an external control light source to vary the dispersion characteristic of the medium via electromagnetically induced transparency effect. We demonstrate that the semiconductor quantum dot structures can be used as a slow-light medium. In such structure, the total buffering time is variable and controlled by an external pump laser. We present a theoretical investigation of the criteria for achieving slow light in semiconductor quantum dots. New pump scheme is proposed to overcome the sample nonuniformity. Finally, optical signal propagation through the semiconductor optical buffer is presented to demonstrate the feasibility for practical applications.
TL;DR: In this article, it was shown that the Bose-Einstein condensate (BEC) wave function can be modeled as a Gaussian-shaped feature in the BEC wave function.
Abstract: We theoretically explore coherent information transfer between ultraslow light pulses and Bose-Einstein condensates (BEC's) and find that storing light pulses in BEC's allows the coherent condensate dynamics to process optical information. We consider BEC's of alkali atoms with a $\ensuremath{\Lambda}$ energy level configuration. In this configuration, one laser (the coupling field) can cause a pulse of a second pulsed laser (the probe field) to propagate with little attenuation (electromagnetically induced transparency) at a very slow group velocity $(\ensuremath{\sim}10\phantom{\rule{0.3em}{0ex}}\mathrm{m}∕\mathrm{s})$ and be spatially compressed to lengths smaller than the BEC. These pulses can be fully stopped and later revived by switching the coupling field off and on. Here we develop a formalism, applicable in both the weak- and strong-probe regimes, to analyze such experiments and establish several results: (1) We show that the switching can be performed on time scales much faster than the adiabatic time scale for electromagnetically induced transparancy even in the strong-probe regime. We also study the behavior of the system changes when this time scale is faster than the excited state lifetime. (2) Stopped light pulses write their phase and amplitude information onto spatially dependent atomic wave functions, resulting in coherent two-component BEC dynamics during long storage times. We investigate examples relevant to $^{87}\mathrm{Rb}$ experimental parameters and see a variety of novel dynamics occur, including interference fringes, gentle breathing excitations, and two-component solitons, depending on the relative scattering lengths of the atomic states used and the probe to coupling intensity ratio. We find that the dynamics when the levels $\ensuremath{\mid}F=1,{M}_{F}=\ensuremath{-}1⟩$ and $\ensuremath{\mid}F=2,{M}_{F}=+1⟩$ are used could be well suited to designing controlled processing of the information input on the probe. (3) Switching the coupling field on after the dynamics writes the evolved BEC wave functions density and phase features onto a revived probe pulse, which then propagates out. We establish equations linking the BEC wave function to the resulting output probe pulses in both the strong- and weak-probe regimes. We then identify sources of deviations from these equations due to absorption and distortion of the pulses. These deviations result in imperfect fidelity of the information transfer from the atoms to the light fields and we calculate this fidelity for Gaussian-shaped features in the BEC wave functions. In the weak-probe case, we find that the fidelity is affected both by absorption of very-small-length-scale features and absorption of features occupying regions near the condensate edge. We discuss how to optimize the fidelity using these considerations. In the strong-probe case, we find that when the oscillator strengths for the two transitions are equal the fidelity is not strongly sensitive to the probe strength, while when they are unequal the fidelity is worse for stronger probes. Applications to distant communication between BEC's, squeezed light generation, and quantum information are anticipated.
TL;DR: In this paper, a polariton description of both phenomena is systematically introduced, which allows one to predict the shapes and phases of both the transmitted pulses and the stored and released ones as well as the atomic coherence in the storage stage.
Abstract: Electromagnetically induced transparency and light storing are discussed in the case of an atomic medium in a double $\ensuremath{\Lambda}$ configuration. A polariton description of both phenomena is systematically introduced. Analytic expressions are given which allow one to predict the shapes and phases of both the transmitted pulses and the stored and released ones as well as the atomic coherence in the storage stage. A comparison of the numerical solutions of the Maxwell-Bloch equations with the results due to the polariton model proves a strong predictive power of the latter.
TL;DR: A considerable deceleration of light pulses in crystals with nearly compensated space-charge field proves that the strong dispersion of dynamic photorefractive gratings in the vicinity of Bragg resonance is of primary importance for light slowing down.
Abstract: A considerable deceleration of light pulses in crystals with nearly compensated space-charge field proves that the strong dispersion of dynamic photorefractive gratings in the vicinity of Bragg resonance is of primary importance for light slowing down.
TL;DR: In this article, an experimental investigation of electromagnetically induced transparency in a multi-level cascade system of cold Rb-85 atoms was performed, where the absorption spectral profiles of the probe light and their dependence on the intensity of the coupling laser were investigated.
TL;DR: It is shown that under certain conditions such a dense gas can exhibit simultaneously negative permittivity and negative permeability, and negligibly small loss.
Abstract: The theoretical mechanism for realizing a negative refractive index material in an optical frequency range with an atomic gas system of electromagnetically induced transparency (EIT) is studied. It is shown that under certain conditions such a dense gas can exhibit simultaneously negative permittivity and negative permeability, and negligibly small loss.