Showing papers on "Electromagnetically induced transparency published in 2006"
TL;DR: In this article, the authors provided the first experimental observation of structure tuning of the electromagnetically induced transparency-like spectrum in integrated on-chip optical resonator systems and measured a transparency-resonance mode with a quality factor of 11 800.
Abstract: We provide the first experimental observation of structure tuning of the electromagnetically induced transparencylike spectrum in integrated on-chip optical resonator systems. The system consists of coupled silicon ring resonators with $10\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$ diameter on silicon, where the coherent interference between the two coupled resonators is tuned. We measured a transparency-resonance mode with a quality factor of 11 800.
623 citations
TL;DR: In this paper, it was shown that the causal, non-instantaneous behavior of any single-photon sensitive nonlinearity is enough to preclude such a high-fidelity operation.
Abstract: By embedding an atom capable of electromagnetically induced transparency inside an appropriate photonic-crystal microcavity it may become possible to realize an optical nonlinearity that can impart a $\ensuremath{\pi}$-rad-peak phase shift in response to a single-photon excitation. Such a device, if it operated at high fidelity, would then complete a universal gate set for all-optical quantum computation. It is shown here that the causal, noninstantaneous behavior of any ${\ensuremath{\chi}}^{(3)}$ nonlinearity is enough to preclude such a high-fidelity operation. In particular, when a single-photon-sensitive ${\ensuremath{\chi}}^{(3)}$ nonlinearity has a response time that is much shorter than the duration of the quantum computer's single-photon pulses, essentially no overall phase shift is imparted to these pulses by cross-phase modulation. Conversely, when this nonlinearity has a response time that is much longer than this pulse duration a single-photon pulse can induce a $\ensuremath{\pi}$-rad overall phase shift through cross-phase modulation, but the phase noise injected by the causal, noninstantaneous response function precludes this from being a high-fidelity operation.
289 citations
21 May 2006
TL;DR: An all-optical analogue to electromagnetically induced transparency due to coherent interference between two coupled resonators is shown experimentally.
Abstract: We show experimentally an all-optical analogue to electromagnetically induced transparency due to coherent interference between two coupled resonators. We measured an EIT-like resonance mode with quality factor of 11,800 using silicon ring resonators.
248 citations
TL;DR: In this article, it was shown that semiconductor nanostructures can be tailored to have "artificial atom" electron states which, for the first time in a solid, also show GWI.
Abstract: When Einstein showed that light amplification needed a collection of atoms in ‘population inversion’ (that is, where more than half the atoms are in an excited state, ready to emit light rather than absorb it) he was using thermodynamic arguments1. Later on, quantum theory predicted2,3 that matter–wave interference effects inside the atoms could, in principle, allow gain without inversion (GWI). The coherent conditions needed to observe this strange effect have been generated in atomic vapours4, but here we show that semiconductor nanostructures can be tailored to have ‘artificial atom’ electron states which, for the first time in a solid, also show GWI. In atomic experiments, the coherent conditions, typically generated either by coupling two electron levels to a third with a strong light beam2,3 or by tunnel coupling both levels to the same continuum (Fano effect5), are also responsible for the observation of ‘electromagnetically induced transparency’ (EIT)6. In turn, this has allowed observations of markedly slowed7 and even frozen8 light propagation. Our ‘artificial atom’ GWI effects are rooted in the same phenomena and, from an analysis of the absorption changes, we infer that the light slows to ∼c/40 over the spectral range where the optical gain appears.
220 citations
TL;DR: In this paper, the effect of spontaneously generated coherence on the Kerr nonlinearity of general three-level systems of three-dimensional (3D) systems was investigated, and it was found that the enhanced Kerr non-linearity can be attributed to the presence of an extra atomic coherence induced by the spontaneously generated Coherence.
Abstract: A theoretical investigation is carried out into the effect of spontaneously generated coherence on the Kerr nonlinearity of general three-level systems of $\ensuremath{\Lambda}$, ladder, and V-shape types. It is found, with spontaneously generated coherence present, that the Kerr nonlinearity can be clearly enhanced. In the $\ensuremath{\Lambda}$- and ladder-type systems, the maximal Kerr nonlinearity increases and at the same time enters the electromagnetically induced transparency window as the spontaneously generated coherence intensifies. As for the V-type system, the absorption property is significantly modified and therefore enhanced Kerr nonlinearity without absorption occurs for certain probe detunings. We attribute the enhancement of Kerr nonlinearity mainly to the presence of an extra atomic coherence induced by the spontaneously generated coherence.
201 citations
TL;DR: In this article, the inner walls of a photonic band-gap fiber are covered with organosilane and light-induced atomic desorption is used to release Rb atoms into the core.
Abstract: We show that rubidium vapor can be produced within the core of a photonic band-gap fiber yielding an optical depth in excess of 2000. Our technique for producing the vapor is based on coating the inner walls of the fiber core with organosilane and using light-induced atomic desorption to release Rb atoms into the core. As an initial demonstration of the potential of this system for supporting ultralow-level nonlinear optical interactions, we perform electromagnetically induced transparency with control-field powers in the nanowatt regime, which represents more than a 1000-fold reduction from the power required for bulk, focused geometries.
173 citations
TL;DR: In this paper, the authors proposed a scheme to create an effective magnetic field for ultracold atoms in a planar geometry, which allows the experimental study of classical and quantum Hall effects in close analogy to solid state systems including the possibility of finite currents.
Abstract: We propose a scheme to create an effective magnetic field for ultracold atoms in a planar geometry. The setup allows the experimental study of classical and quantum Hall effects in close analogy to solid-state systems including the possibility of finite currents. The present scheme is an extention of the proposal in Phys. Rev. Lett. 93, 033602 (2004), where the effective magnetic field is now induced for three-level Lambda-type atoms by two counterpropagating laser beams with shifted spatial profiles. Under conditions of electromagnetically induced transparency the atom-light interaction has a space-dependent dark state, and the adiabatic center-of-mass motion of atoms in this state experiences effective vector and scalar potentials. The associated magnetic field is oriented perpendicular to the propagation direction of the laser beams. The field strength achievable is one flux quantum over an area given by the transverse beam separation and the laser wavelength. For a sufficiently dilute gas the field is strong enough to reach the lowest Landau level regime.
140 citations
TL;DR: A low-light-level cross-phase-modulation (XPM) scheme based on the light-storage technique in laser-cooled 87Rb atoms that makes possible conditional phase shifts on the order of pi with single photons is experimentally demonstrated.
Abstract: We experimentally demonstrate a low-light-level cross-phase-modulation (XPM) scheme based on the light-storage technique in laser-cooled $^{87}\mathrm{Rb}$ atoms. The proposed scheme can achieve a similar phase shift and has the same figure of merit as one using static electromagnetically induced transparency under the constant coupling field. Nevertheless, the phase shift and the energy loss of a probe pulse induced by a signal pulse are neither influenced by the coupling intensity nor by the atomic optical density in the light-storage XPM scheme. This scheme enhances the flexibility of the experiment and makes possible conditional phase shifts on the order of $\ensuremath{\pi}$ with single photons.
128 citations
TL;DR: In ultracold atomic samples the gap is found to arise from spatial regions where Autler-Townes splitting and electromagnetically induced transparency alternate with one another and detailed calculations show that accurate and efficient coherent optical control of the gap can be accomplished.
Abstract: Resonantly absorbing media supporting electromagnetically induced transparency may give rise to specific periodic patterns where a light probe is found to experience a fully developed photonic band gap yet with negligible absorption everywhere. In ultracold atomic samples the gap is found to arise from spatial regions where Autler-Townes splitting and electromagnetically induced transparency alternate with one another and detailed calculations show that accurate and efficient coherent optical control of the gap can be accomplished. The remarkable experimental simplicity of the control scheme would ease quantum nonlinear optics applications.
122 citations
TL;DR: It is shown that left-handed properties can be electromagnetically induced in a general four-level atomic medium for a finite spectral range and inside an experimentally reachable domain of parameters.
Abstract: We show that left-handed properties can be electromagnetically induced in a general four-level atomic medium for a finite spectral range. We use an electric (magnetic) atomic transition as an electric (magnetic) resonator to modify the permittivity (permeability), both at the same frequency. The implementation of the four-level model is carried out in atomic hydrogen and neon. In each case the existence of left-handed properties is predicted inside an experimentally reachable domain of parameters.
122 citations
TL;DR: A feasible preparational procedure is suggested for the atomic initial state to achieve matched group velocities for both signal fields and to avoid cancellation effects through the nonlinear Zeeman effect.
Abstract: We propose a scheme to generate double electromagnetically induced transparency and optimal cross-phase modulation for two slow, copropagating pulses with matched group velocities in a single species of atom, namely $^{87}\mathrm{Rb}$. A single pump laser is employed and a homogeneous magnetic field is utilized to avoid cancellation effects through the nonlinear Zeeman effect. We suggest a feasible preparational procedure for the atomic initial state to achieve matched group velocities for both signal fields.
TL;DR: In this paper, the authors demonstrate switching of a single signal photon by a single gating photon of a different frequency via a cross-phase modulation, mediated by materials exhibiting electromagnetically induced transparency (EIT), which are embedded in photonic crystals (PhCs).
Abstract: This paper demonstrates switching of a single signal photon by a single gating photon of a different frequency, via a cross-phase-modulation. This effect is mediated by materials exhibiting electromagnetically induced transparency (EIT), which are embedded in photonic crystals (PhCs). An analytical model based on waveguide-cavity QED is constructed for our system, which consists of a PhC waveguide and a PhC microcavity containing a four-level EIT atom. It is solved exactly and analyzed using experimentally accessible parameters. It is found that the strong coupling regime is required for lossless two-photon quantum entanglement.
TL;DR: A four-level atomic system with electromagnetically induced transparency with giant chi(3) and chi(5) susceptibilities of opposite signs will allow us to obtain multidimensional solitons and light condensates with surface tension properties analogous to those of usual liquids.
Abstract: We study a four-level atomic system with electromagnetically induced transparency with giant ${\ensuremath{\chi}}^{(3)}$ and ${\ensuremath{\chi}}^{(5)}$ susceptibilities of opposite signs. This system will allow us to obtain multidimensional solitons and light condensates with surface tension properties analogous to those of usual liquids.
TL;DR: The coherent blue output is enhanced by several mechanisms, including stronger coupling to a larger fraction of the atomic population, operation at a detuning such that the vapor is nominally transparent to the 780 nm pump field, reduced losses owing to optical pumping, and optimal phase matching.
Abstract: We demonstrate production of continuous coherent blue laser light by using a five-level system in rubidium vapor. Two low-power lasers, at 780 and 776 nm, induce strong atomic coherence in the 5S-5P-5D states. The atoms decay to the 6P excited state, from which stimulated emission produces a coherent blue (420 nm) beam. We have coupled both ground-state hyperfine levels, effecting coherence between four levels. The coherent blue output is enhanced by several mechanisms, including stronger coupling to a larger fraction of the atomic population, operation at a detuning such that the vapor is nominally transparent to the 780 nm pump field, reduced losses owing to optical pumping, and optimal phase matching. We report experimental findings and compare them with results from a semiclassical Maxwell-Bloch model.
TL;DR: In this paper, the authors demonstrate theoretically that there exists electromagnetically induced transparency in an asymmetric double quantum dot system using tunneling instead of pump laser, and they theoretically analyze the group velocity slowdown factor as a function of electron tunneling at different broadened linewidths.
Abstract: The authors demonstrate theoretically that there exists electromagnetically induced transparency in an asymmetric double quantum dot system using tunneling instead of pump laser. The group velocity slowdown factor is theoretically analyzed as a function of electron tunneling at different broadened linewidths. With feasible parameters for applications to a 100Gbits∕s optical network, numerical calculation infers group velocity as low as 300m∕s. The scheme is expected to be useful in constructing a variable semiconductor optical buffer based on electromagnetically induced transparency in an asymmetric double quantum dot controlled by voltage.
TL;DR: A theoretical analysis of the results shows that dephasing in the ground state is the main source of decoherence, with population exchange playing a minor role.
Abstract: We report characterization of electromagnetically induced transparency (EIT) resonances in the D1 line of 87Rb under various experimental conditions. The dependence of the EIT linewidth on the power of the pump field was investigated at various temperatures for the ground states of the lambda system associated with different hyperfine levels of the atomic 5S1/2 state as well as magnetic sublevels of the same hyperfine level. Strictly linear behavior was observed in all cases. A theoretical analysis of our results shows that dephasing in the ground state is the main source of decoherence, with population exchange playing a minor role.
TL;DR: Direct time-domain measurement of tunable optical delay in a silicon resonating structure composed by a double-ring resonator, whose spectrum has a narrow transparency peak with low group velocity analogous to that in electromagnetically induced transparency is presented.
Abstract: Direct time-domain measurement of tunable optical delay in a silicon resonating structure is presented. The structure is composed by a double-ring resonator, whose spectrum has a narrow transparency peak with low group velocity analogous to that in electromagnetically induced transparency. Effective group indices from 90 to 290 are obtained by tuning the resonator thermally. The measurements agree well with the theoretical analysis.
TL;DR: It is demonstrated that strongly anisotropic planar dielectric systems can be used to create waveguides supporting modes with extremely slow group velocity and used for 3D imaging, with a potential for subwavelength resolution.
Abstract: We demonstrate that strongly anisotropic planar dielectric systems can be used to create waveguides supporting modes with extremely slow group velocity. Furthermore, we show that such systems can be used for 3D imaging, with a potential for subwavelength resolution.
TL;DR: In this paper, it was shown that light passing through a Rubidium gas cell, under the conditions of electromagnetically induced transparency, is deflected by a small magnetic field gradient.
Abstract: Electromagnetically induced transparency allows light transmission through dense atomic media by means of quantum interference1. Media with electromagnetically induced transparency have very interesting properties, such as extremely slow group velocities2,3,4. Quasiparticles, the so-called dark polaritons, which are mixtures of a photonic and an atomic contribution5, are associated with slow light propagation. Here, we demonstrate that these excitations behave as particles with a non-zero magnetic moment, which is in clear contrast to the properties of a free photon. It is found that light passing through a rubidium gas cell, under the conditions of electromagnetically induced transparency, is deflected by a small magnetic field gradient. The deflection angle is proportional to the optical propagation time through the cell. The beam deflection observed can be understood by assuming that dark-state polaritons have an effective magnetic moment. Our experiment can be described in terms of a Stern–Gerlach experiment for the polaritons.
TL;DR: In this article, the dependence of the EIT linewidth on the power of the pump field was investigated, at various temperatures, for the ground states of the lambda-system associated with different hyperfine levels of the atomic 5S_1/2 state as well as magnetic sublevels of the same hyperfine level.
Abstract: We report characterization of electromagnetically induced transparency (EIT) resonances in the D1 line of Rb-87 under various experimental conditions. The dependence of the EIT linewidth on the power of the pump field was investigated, at various temperatures, for the ground states of the lambda-system associated with different hyperfine levels of the atomic 5S_1/2 state as well as magnetic sublevels of the same hyperfine level. Strictly linear behavior was observed in all cases. A theoretical analysis of our results shows that dephasing in the ground state is the main source of decoherence, with population exchange playing a minor role.
TL;DR: A generalized scheme for phase-conjugate resonant 2n-wave mixing, which has a high efficiency and is easy for phase matching, is proposed, which may find wide application in related areas such as coherent transientSpectroscopy, Autler-Townes spectroscopy and electromagnetically induced transparency.
Abstract: A generalized scheme for phase-conjugate resonant 2n-wave mixing, which has a high efficiency and is easy for phase matching, is proposed As a new type of coherent laser spectroscopy this approach can be employed for studying highly excited atomic states or states with a high angular momentum To demonstrate its feasibility we have studied the doubly excited autoionizing Rydberg states of Ba by phase-conjugate six-wave mixing, and have furthermore achieved eight-wave mixing in Na This method may find wide application in related areas such as coherent transient spectroscopy, Autler-Townes spectroscopy and electromagnetically induced transparency In particular, it may provide new insights into the nature of highly excited states
TL;DR: In this article, preliminary results from an experimental study of slow light in anti-relaxation-coated Rb vapour cells are presented, and the construction and testing of such cells are described.
Abstract: Preliminary results from an experimental study of slow light in anti-relaxation-coated Rb vapour cells are presented, and the construction and testing of such cells are described. The slow ground state decoherence rate allowed by coated cell walls leads to a dual-structured electromagnetically induced transparency (EIT) spectrum with a very narrow (< 100 Hz) transparency peak on top of a broad pedestal. Such dual-structured EIT permits optical probe pulses to propagate with greatly reduced group velocity on two time scales. Ongoing efforts to optimize the pulse delay in such coated cell systems are discussed.
TL;DR: In this paper, a quantum left-handed metamaterial is proposed, which is composed of an array of superconducting quantum-interference devices and a dielectric background.
Abstract: A scheme for a kind of quantum left-handed metamaterial is proposed, which is composed of an array of superconducting quantum-interference devices and a dielectric background. Based on an analytical study, it is shown that (the real part of) the magnetic permeability $\ensuremath{\mu}$ can be negative with low loss and its frequency dependence is different from that of ordinary split-ring resonators. The structural requirements and frequency range for negative permeability are derived. Moreover, the permeability can be smoothly tuned over a large range by another (coupling) field via a quantum interference, which is similar to electromagnetically induced transparency of atomic systems. Negative refractivity with low loss can be achieved by tuning the permeability.
TL;DR: It is shown that the EIT system adds excess noise to the delayed light that has not hitherto been predicted by published theoretical modeling.
Abstract: Using electromagnetically induced transparency (EIT), it is possible to delay and store light in atomic ensembles. Theoretical modeling and recent experiments have suggested that the EIT storage mechanism can be used as a memory for quantum information. We present experiments that quantify the noise performance of an EIT system for conjugate amplitude and phase quadratures. It is shown that our EIT system adds excess noise to the delayed light that has not hitherto been predicted by published theoretical modeling. In analogy with other continuous-variable quantum information systems, the performance of our EIT system is characterized in terms of conditional variance and signal transfer.
TL;DR: In this article, it was shown that the quantum evolution of the pumped couplers can be closed in a two-qubit Hilbert space spanned by vacuum and single-photon states only.
Abstract: Schemes for optical-state truncation of two cavity modes are analysed. The systems, referred to as the nonlinear quantum scissors devices, comprise two coupled nonlinear oscillators (Kerr nonlinear coupler) with one or two of them pumped by external classical fields. It is shown that the quantum evolution of the pumped couplers can be closed in a two-qubit Hilbert space spanned by vacuum and single-photon states only. Thus, the pumped couplers can behave as a two-qubit system. Analysis of time evolution of the quantum entanglement shows that Bell states can be generated. A possible implementation of the couplers is suggested in a pumped double-ring cavity with resonantly enhanced Kerr nonlinearities in an electromagnetically induced transparency scheme. The fragility of the generated states and their entanglement due to the standard dissipation and phase damping are discussed by numerically solving two types of master equations.
TL;DR: In this article, a quantum manipulation of a traveling light pulse using electromagnetically induced transparency-based slow light phenomenon for the generation of two-color stationary light was presented.
Abstract: We present a quantum manipulation of a traveling light pulse using electromagnetically induced transparency-based slow light phenomenon for the generation of two-color stationary light. We theoretically discuss the two-color stationary light for the quantum wavelength conversion process in terms of pulse area, energy transfer, and propagation directions. The condition of the two-color stationary light pulse generation has been found and the quantum light dynamics has been studied analytically in the adiabatic limit. The quantum frequency conversion rate of the traveling light is dependent on the spatial spreading of the two-color stationary light pulse and can be near unity in an optically dense medium for the optimal frequencies of the control laser fields.
TL;DR: A novel and easy-to-implement hollow-core photonic crystal fiber cell fabrication technique based on helium diffusion through silica, where the formed gas cells combine low optical insertion loss and vacuum acetylene pressure.
Abstract: We report a novel and easy-to-implement hollow-core photonic crystal fiber cell fabrication technique based on helium diffusion through silica. The formed gas cells combine low optical insertion loss (1.8 dB) and vacuum acetylene pressure (μbar regime). The estimates of the final gas pressure, using both Voigt interpolation and electromagnetically induced transparency, show a good match with the initial fitting pressure.
TL;DR: In this article, a dual-structured electromagnetically induced transparency (EIT) spectrum with a very narrow (<100 Hz) transparency peak on top of a broad pedestal is presented.
Abstract: We present preliminary results from an experimental study of slow light in anti-relaxation-coated Rb vapor cells, and describe the construction and testing of such cells. The slow ground state decoherence rate allowed by coated cell walls leads to a dual-structured electromagnetically induced transparency (EIT) spectrum with a very narrow (<100 Hz) transparency peak on top of a broad pedestal. Such dual-structure EIT permits optical probe pulses to propagate with greatly reduced group velocity on two time scales. We discuss ongoing efforts to optimize the pulse delay in such coated cell systems.
TL;DR: In this article, a hollow-core-PCFCCF filled with acetylene at sub-millibar pressure was used for the generation of electromagnetically induced transparency at cryogenic temperature.
TL;DR: In this paper, a mechanism to achieve coherent control of the polarization rotation of an optical field in a multilevel EIT system in rubidium atoms was proposed and experimentally demonstrated, where the symmetry of the atomic medium to the propagation of two orthogonal polarization components of a weak linearly polarized probe field was broken.
Abstract: We propose and experimentally demonstrate a mechanism to achieve coherent control of the polarization rotation of an optical field in a multilevel electromagnetically induced transparency (EIT) system in rubidium atoms. By choosing a properly polarized coupling field and transition energy levels, the symmetry of the atomic medium to the propagation of two orthogonal polarization components of a weak linearly polarized probe field can be broken, which leads to a coherently controlled rotation of the probe field polarization. This mechanism of coherently controlled optical polarization rotation makes use of asymmetry in EIT subsystems for the two circular polarization components of the probe beam with a contribution from different transition strengths (due to different Clebsh-Gordan coefficients) in this multilevel atomic system.