Showing papers on "Electromagnetically induced transparency published in 2008"
TL;DR: A plasmonic "molecule" consisting of a radiative element coupled with a subradiant (dark) element is theoretically investigated and shows electromagnetic response that closely resembles the electromagnetically induced transparency in an atomic system.
Abstract: A plasmonic "molecule" consisting of a radiative element coupled with a subradiant (dark) element is theoretically investigated. The plasmonic molecule shows electromagnetic response that closely resembles the electromagnetically induced transparency in an atomic system. Because of its subwavelength dimension, this electromagnetically induced transparency-like molecule can be used as a building block to construct a "slow light" plasmonic metamaterial.
2,088 citations
TL;DR: It is shown that pulses propagating through such metamaterials experience considerable delay, and the thickness of the structure along the direction of wave propagation is much smaller than the wavelength, which allows successive stacking of multiple meetamaterial slabs leading to increased transmission and bandwidth.
Abstract: We demonstrate a classical analog of electromagnetically induced transparency in a planar metamaterial. We show that pulses propagating through such metamaterials experience considerable delay. The thickness of the structure along the direction of wave propagation is much smaller than the wavelength, which allows successive stacking of multiple metamaterial slabs leading to increased transmission and bandwidth.
775 citations
TL;DR: Storage and retrieval of a squeezed vacuum was successfully demonstrated using electromagnetically induced transparency and was confirmed using the time-domain homodyne method.
Abstract: Storage and retrieval of a squeezed vacuum was successfully demonstrated using electromagnetically induced transparency. The squeezed vacuum pulse having a temporal width of 930 ns was incident on the laser cooled 87Rb atoms with an intense control light in a coherent state. When the squeezed vacuum pulse was slowed and spatially compressed in the cold atoms, the control light was switched off. After 3 mus of storage, the control light was switched on again, and the squeezed vacuum was retrieved, as was confirmed using the time-domain homodyne method.
220 citations
TL;DR: In this paper, the authors studied the low-intensity light pulse propagation through an asymmetric double quantum well via Fano-type interference based on intersubband transitions and showed the generation of ultraslow bright and dark optical solitons in this system.
Abstract: We study the low-intensity light pulse propagation through an asymmetric double quantum well via Fano-type interference based on intersubband transitions. The propagation of the pulse across the quantum well is studied analytically and numerically with the coupled Maxwell-Schr\"odinger equations. We show the generation of ultraslow bright and dark optical solitons in this system. Whether the solitons are dark and bright can be controlled by the ratio of dipole moments of the intersubband transitions. Such investigation of ultraslow optical solitons in the present work may lead to important applications such as high-fidelity optical delay lines and optical buffers in semiconductor quantum wells structure.
169 citations
TL;DR: The observation of low-light level optical interactions in a tapered optical nanofiber (TNF) embedded in a hot rubidium vapor makes it a very promising candidate for ultralow power resonant nonlinear optical applications.
Abstract: We report the observation of low-light level optical interactions in a tapered optical nanofiber (TNF) embedded in a hot rubidium vapor The small optical mode area plays a significant role in the optical properties of the hot vapor Rb-TNF system, allowing nonlinear optical interactions with nW level powers even in the presence of transit-time dephasing rates much larger than the intrinsic linewidth We demonstrate nonlinear absorption and V-type electromagnetically induced transparency with cw powers below 10 nW, comparable to the best results in any Rb-optical waveguide system The good performance and flexibility of the Rb-TNF system makes it a very promising candidate for ultralow power resonant nonlinear optical applications
160 citations
TL;DR: In this work, arbitrary two-dimensional images are slowed and stored in warm atomic vapor for up to 30 micros, utilizing electromagnetically induced transparency, with main limitation on the storage resolution and duration.
Abstract: Reversible and coherent storage of light in an atomic medium is a promising method with possible applications in many fields. In this work, arbitrary two-dimensional images are slowed and stored in warm atomic vapor for up to $30\text{ }\text{ }\ensuremath{\mu}\mathrm{s}$, utilizing electromagnetically induced transparency. Both the intensity and the phase patterns of the optical field are maintained. The main limitation on the storage resolution and duration is found to be the diffusion of atoms. A technique analogous to phase-shift lithography is employed to diminish the effect of diffusion on the visibility of the reconstructed image.
147 citations
TL;DR: In this paper, the authors describe the process using cold atomic-gas media to generate nonclassical light, especially focusing on narrowband biphoton generation, and show that both linear and nonlinear optical responses to the generated fields play an important role in determining the two-photon temporal correlation.
Abstract: Generating nonclassical light offers a benchmark tool for fundamental research and potential applications in quantum optics. Conventionally, it has become a standard technique to produce nonclassical light through the nonlinear optical processes occurring in nonlinear crystals. We describe this process using cold atomic-gas media to generate such nonclassical light, especially focusing on narrowband biphoton generation. Compared with the standard procedure the new biphoton source has such properties as long coherence time, long coherence length, high spectral brightness, and high conversion efficiency. Although there exist two methodologies describing the physical process, we concentrate on the theoretical aspect of the entangled two-photon state produced from the four-wave mixing in a multilevel atomic ensemble using perturbation theory. We show that both linear and nonlinear optical responses to the generated fields play an important role in determining the biphoton waveform and, consequently, on the two-photon temporal correlation. There are two characteristic regimes determined by whether the linear or nonlinear coherence time is dominant. In addition, our model provides a clear physical picture that brings insight into understanding biphoton optics with this new source. We apply our model to recent work on generating narrowband (and even subnatural linewidth) paired photons using the technique of electromagnetically induced transparency and slow-light effect in cold atoms and find good agreement with experimental results.
142 citations
TL;DR: In this article, the authors proposed a new method for quantum optical control with nanoscale resolution, which allows coherent far-field manipulation of individual quantum systems with spatial selectivity that is not limited by the wavelength of radiation and can, in principle, approach a few nanometers.
Abstract: We suggest a new method for quantum optical control with nanoscale resolution. Our method allows for coherent far-field manipulation of individual quantum systems with spatial selectivity that is not limited by the wavelength of radiation and can, in principle, approach a few nanometers. The selectivity is enabled by the nonlinear atomic response, under the conditions of electromagnetically induced transparency, to a control beam with intensity vanishing at a certain location. Practical performance of this technique and its potential applications to quantum information science with cold atoms, ions, and solid-state qubits are discussed.
141 citations
TL;DR: In this paper, the authors studied single-photon transport in an array of coupled microcavities where two two-level atomic systems are embedded in two separate cavities of the array.
Abstract: We study single-photon transport in an array of coupled microcavities where two two-level atomic systems are embedded in two separate cavities of the array. We find that a single photon can be totally reflected by a single two-level system. However, two separate two-level systems can also create, between them, single-photon quasibound states. Therefore, a single two-level system in the cavity array can act as a mirror while a different type of cavity can be formed by using two two-level systems, acting as tunable "mirrors," inside two separate cavities in the array. In analogy with superlattices in solid state physics, we call this "cavity inside a coupled-cavity array" a supercavity. This supercavity is the quantum analog of Fabry-Perot interferometers. Moreover, we show that the physical properties of this quantum supercavity can be adjusted by changing the frequencies of these two-level systems.
136 citations
TL;DR: In this article, a time-reversal-based iteration procedure was proposed to find the optimal input signal pulse shape for any given control field, and a procedure based on the calculation of an optimal control field for any signal pulse shapes.
Abstract: We study procedures for the optimization of efficiency of light storage and retrieval based on the dynamic form of electromagnetically induced transparency in hot Rb vapor. We present a detailed analysis of two recently demonstrated optimization protocols: a time-reversal-based iteration procedure, which finds the optimal input signal pulse shape for any given control field, and a procedure based on the calculation of an optimal control field for any given signal pulse shape. We verify that the two procedures are mutually consistent and that they both independently achieve the maximum memory efficiency for any given optical depth. We observe good agreement with theoretical predictions for moderate optical depths $(l25)$, while at higher optical depths the experimental efficiency falls below the theoretically predicted values. We identify possible effects responsible for this reduction in memory efficiency.
117 citations
TL;DR: The theory of these resonances in a Doppler-broadened medium is developed and the results of experimental observations of these spectra in three-level Lambda-type rubidium atoms inside an optical ring cavity are presented.
Abstract: The transmission spectrum of three-level atoms in a vapor cell inside an optical cavity shows distinct peaks associated with atom-cavity polaritons in the system. We develop the theory of these resonances in a Doppler-broadened medium and present the results of experimental observations of these spectra in three-level $\ensuremath{\Lambda}$-type rubidium atoms inside an optical ring cavity.
TL;DR: It is shown that pairs of atoms optically excited to the Rydberg states can strongly interact with each other via effective long-range dipole-dipole or van der Waals interactions mediated by their nonresonant coupling to a common microwave field mode of a superconducting coplanar waveguide cavity.
Abstract: We show that pairs of atoms optically excited to the Rydberg states can strongly interact with each other via effective long-range dipole-dipole or van der Waals interactions mediated by their nonresonant coupling to a common microwave field mode of a superconducting coplanar waveguide cavity. These cavity mediated interactions can be employed to generate single photons and to realize in a scalable configuration a universal phase gate between pairs of single photon pulses propagating or stored in atomic ensembles in the regime of electromagnetically induced transparency.
TL;DR: The system and enhanced cross-Kerr nonlinearities presented here can be applied to quantum information processes.
Abstract: We report experimental observations on the simultaneous electromagnetically induced transparency (EIT) effects for probe and trigger fields (double EIT) as well as the enhanced cross-phase modulation (XPM) between the two fields in a four-level tripod EIT system of the D1 line of 87Rb atoms. The XPM coefficients (larger than 2 x 10(-5) cm2/W) and the accompanying transmissions (higher than 60%) are measured at a slight detuning of the probe field from the exact EIT-resonance condition. The system and enhanced cross-Kerr nonlinearities presented here can be applied to quantum information processes.
TL;DR: In this paper, a three-photon resonant nondegenerate six-wave mixing (NSWM) was reported in a dressed cascade five-level system, where phase match condition is not stringent and NSWM signal is enhanced tremendously due to the multiple resonance with the atomic transition frequencies.
Abstract: We report a three-photon resonant nondegenerate six-wave mixing (NSWM) in a dressed cascade five-level system It has advantages that phase match condition is not stringent and NSWM signal is enhanced tremendously due to the multiple resonance with the atomic transition frequencies In the presence of a strong coupling Held, the three-photon resonant NSWM spectrum exhibits Autler-Townes splitting This technique provides a spectroscopic tool for measuring not only the resonant frequency and dephasing rate but also the transition dipole moment between two highly excited atomic states
TL;DR: In this paper, the authors considered the effect of a second mechanical mode with a close but different resonance frequency and showed that the nearby mechanical resonance is simultaneously cooled by the cavity field, provided that the difference between the two mechanical frequencies is not too small.
Abstract: Laser cooling of a mechanical mode of a resonator by the radiation pressure of a detuned optical cavity mode has been recently demonstrated by various groups in different experimental configurations. Here, we consider the effect of a second mechanical mode with a close but different resonance frequency. We show that the nearby mechanical resonance is simultaneously cooled by the cavity field, provided that the difference between the two mechanical frequencies is not too small. When this frequency difference becomes smaller than the effective mechanical damping of the secondary mode, the two cooling processes interfere destructively similarly to what happens in electromagnetically induced transparency, and cavity cooling is suppressed in the limit of identical mechanical frequencies. We show that also the entanglement properties of the steady state of the tripartite system crucially depend upon the difference between the two mechanical frequencies. If the latter is larger than the effective damping of the second mechanical mode, the state shows fully tripartite entanglement and each mechanical mode is entangled with the cavity mode. If instead, the frequency difference is smaller, the steady state is a two-mode biseparable state, inseparable only when one splits the cavity mode from the two mechanical modes. In this latter case, the entanglement of each mechanical mode with the cavity mode is extremely fragile with respect to temperature.
TL;DR: In this article, the authors developed a quantum theory to systematically describe the spatial motion of polaritons in inhomogeneous magnetic and optical fields, which can be used to explain the slow light propagation with the mechanism of electromagnetic induced transparency.
Abstract: Polaritons are the collective excitations of many atoms dressed by resonant photons, which can be used to explain the slow light propagation with the mechanism of electromagnetically induced transparency. As quasiparticles, these collective excitations possess the typical feature of the matter particles, which can be reflected and deflected by the inhomogeneous medium in its spatial motion with some velocity. In this paper we develop a quantum theory to systematically describe the spatial motion of polaritons in inhomogeneous magnetic and optical fields. This theoretical approach treats these quasiparticles through an effective Schrodinger equation with anisotropic dispersion that the longitudinal motion is similar to an ultrarelativistic motion of a "slow light velocity" while the transverse motion is of nonrelativity with certain effective mass. We find that, after passing through the EIT medium, the light ray bends due to the spatial-dependent profile of external field. This phenomenon explicitly demonstrates the exotic corpuscular and anisotropic property of polaritons.
TL;DR: In this article, a coherent absorption dip in pump-probe experiment performed on a ten layer optically thin InGaAs/GaAs quantum dot (QD) structure has been observed.
Abstract: A coherent absorption dip in pump-probe experiment performed on a ten layer optically thin InGaAs/GaAs quantum dot (QD) structure has been observed. Measurements performed for different wavelengths ...
TL;DR: In this article, an approach to broadband cloaking of light waves is analyzed for a simplified case of a scaling transformation for a general cylindrical coordinate system, which requires metamaterials with specifically engineered dispersion.
Abstract: An approach to broadband cloaking of light waves is analysed for a simplified case of a scaling transformation for a general cylindrical coordinate system. The proposed approach requires metamaterials with specifically engineered dispersion. The restriction on the signs of gradients in the dispersion dependencies of the dielectric permittivity and the magnetic permeability for different operational wavelengths is revealed and is shown to cause difficulties unless additional gain-assisted compensation for losses or electromagnetically induced transparency is introduced in the cloaking system.
TL;DR: A novel effect of the coupled-resonator-induced reflection (CRIR) characterized by a very high and easily tunable quality factor of the reflection line, for the case of the inter-site coupling between the cavities and the waveguide.
Abstract: We study the resonant transmission of light in a coupled-resonator optical waveguide interacting with two nearly identical side cavities. We reveal and describe a novel effect of the coupled-resonator-induced reflection (CRIR) characterized by a very high and easily tunable quality factor of the reflection line, for the case of the inter-site coupling between the cavities and the waveguide. This effect differs sharply from the coupled-resonator-induced transparency (CRIT)--an all-optical analogue of the electromagnetically-induced transparency--which has recently been studied theoretically and experimentally for the structures based on micro-ring resonators and photonic crystal cavities. Both CRIR and CRIT effects have the same physical origin which can be attributed to the Fano-Feshbach resonances in the systems exhibiting more than one resonance. We discuss the applicability of the novel CRIR effect to the control of the slow-light propagation and low-threshold all-optical switching.
TL;DR: In this paper, the authors demonstrate laser frequency stabilization to excited state transitions using cascade electromagnetically induced transparency (EIT) using a room temperature Rb vapor cell as a reference.
Abstract: We demonstrate laser frequency stabilization to excited state transitions using cascade electromagnetically induced transparency (EIT). Using a room temperature Rb vapor cell as a reference, we stabilize a first diode laser to the D2 transition and a second laser to a transition from the intermediate state to a Rydberg state with principal quantum number n=19 - 70. A combined laser linewidth of 280 kHz over a 0.1 ms time period is achieved. This method may be applied generally to any cascade system and allows laser stabilization to an atomic reference in the absence of strong optical transitions.
TL;DR: An experimental observation of slow light propagation in cold Rb atoms exhibiting cavity electromagnetically induced transparency (EIT) and a combination of the cavity and the EIT atomic system significantly improves the performance of theslow light propagation.
Abstract: We report an experimental observation of slow light propagation in cold Rb atoms exhibiting cavity electromagnetically induced transparency (EIT). The steep slope of the atomic dispersion manifested by EIT reduces the light group velocity. The cavity filtering and feedback further contribute to the slowdown and delay of the light pulse propagation. A combination of the cavity and the EIT atomic system significantly improves the performance of the slow light propagation. A propagation time delay of ~200 ns was observed in the cavity and Rb EIT system, which is ~70 times greater than the time delay calculated for the light pulse propagation through the same Rb EIT system without the cavity.
TL;DR: In this paper, a Lambda-type three-level atom is placed inside one of the cavities in the array and behaves as a functional quantum node (FQN).
Abstract: We study the coherent scattering process of a single photon confined in an one-dimensional (1D) coupled cavity-array, where a Lambda-type three-level atom is placed inside one of the cavities in the array and behaves as a functional quantum node (FQN). We show that, through the electromagnetically-induced-transparency mechanism, the Lambda-type FQN bears complete control over the reflection and transmission of the incident photon along the cavity array. We also demonstrate the emergence of a quasibound state of the single photon inside a secondary cavity constructed by two distant FQN's as two end mirrors, from which we are motivated to design an all-optical single photon storage device of quantum coherence.
TL;DR: It is shown that an EIT medium near the interface between a dielectric and a negative-index metamaterial can establish tight longitudinal and transverse confinement plus extreme slowing of surface polaritons, in both transverse electric andTransverse magnetic polarizations, while simultaneously avoiding losses.
Abstract: We propose fast all-optical control of surface polaritons by placing an electromagnetically induced transparency (EIT) medium at an interface between two materials. EIT provides longitudinal compression and a slow group velocity, while matching properties of the two materials at the interface provides strong transverse confinement. In particular, we show that an EIT medium near the interface between a dielectric and a negative-index metamaterial can establish tight longitudinal and transverse confinement plus extreme slowing of surface polaritons, in both transverse electric and transverse magnetic polarizations, while simultaneously avoiding losses.
TL;DR: In this article, the authors obtained subnatural linewidth for probe absorption in room-temperature Rb vapor using electromagnetically induced transparency (EIT) in a Lambda system.
Abstract: We obtain subnatural linewidth (i.e., $<\Gamma$) for probe absorption in room-temperature Rb vapor using electromagnetically induced transparency (EIT) in a \Lambda system. For stationary atoms, the EIT dip for a resonant control laser is roughly one-half as wide as the control Rabi frequency $\Omega_c$. But in thermal vapor, the moving atoms fill the transparency band so that the final EIT dip remains subnatural even when $\Omega _c \gg \Gamma$. We observe a linewidth of $\Gamma /4$ for $\Omega _c = 8\Gamma$ in the $D_2$ line of Rb.
TL;DR: The spectral range of observed squeezing matches well typical bandwidths of electromagnetically induced transparency (EIT) resonances, making this simple technique for generation of optical fields with nonclassical statistics at atomic transitions wavelengths attractive for EIT-based quantum information protocols applications.
Abstract: We observed squeezed vacuum light at 795 nm in (87)Rb vapor via resonant polarization self-rotation and report noise sidebands suppression of approximately 1 dB below shot-noise level spanning from 30 kHz to 1.2 MHz frequencies. To our knowledge, this is the first demonstration of submegahertz quadrature vacuum squeezing in atomic systems. The spectral range of observed squeezing matches well typical bandwidths of electromagnetically induced transparency (EIT) resonances, making this simple technique for generation of optical fields with nonclassical statistics at atomic transitions wavelengths attractive for EIT-based quantum information protocols applications.
TL;DR: In this article, the authors studied electromagnetically induced transparency (EIT) of a weakly interacting cold Rydberg gas and showed that the onset of interactions is manifest as a depopulation of the Rydenberg state.
Abstract: We study electromagnetically induced transparency (EIT) of a weakly interacting cold Rydberg gas. We show that for Rydberg states with principal quantum numbers in the range n = 19–26, the onset of interactions is manifest as a depopulation of the Rydberg state. In the limit of a weak probe where the depopulation effect is negligible, we observe no evidence of interaction-induced decoherence and obtain a narrow Rydberg dark resonance with a linewidth of <600 kHz.
TL;DR: This paper reveals that most previous results for the ladder-type EIT include the DROP effect, and can observe the double structure transmittance spectrum, a narrow spectrum due to the EIT and a broad spectrum in the 5S1/2(F=2)-5P3/2 (F'=3)-5D5/2
Abstract: We present the double resonance optical pumping (DROP) effect of ladder-type electromagnetically induced transparency (EIT) in the 5S1/2- 5P3/2-5D5/2 transition of 87Rb atoms. When many atoms of the ladder-type atomic system are simultaneously resonant with the two laser fields, the population of one ground state can be optically pumped into another ground state through intermediate states and excited states. In this paper, we reveal that most previous results for the ladder-type EIT include the DROP effect. When the probe laser is very weak and the coupling laser is strong, we can observe the double structure transmittance spectrum, a narrow spectrum due to the EIT and a broad spectrum due to the DROP, in the 5S1/2(F=2)- 5P3/2(F’=3)-5D5/2(F”=4) cycling transition.
TL;DR: In this paper, the effect of a control beam on a Lambda electromagnetically induced transparency (EIT) system in 87Rb has been studied, where the control beam couples one ground state to another excited state forming a four level N-system.
Abstract: We study the effect of a control beam on a Lambda electromagnetically induced transparency (EIT) system in 87Rb. The control beam couples one ground state to another excited state forming a four level N-system. Phase coherent beams to drive the N-system are produced using a double injection scheme. We show that the control beam can be used to Stark shift or split the EIT resonance. Finally, we show that the when the control beam is on-resonance one observes a Doppler-free and sub-natural absorptive resonance with a width of order 100 kHz. Crucially, this narrow absorptive resonance only occurs when atoms with a range of velocities are present, as is the case in a room temperature vapour.
TL;DR: In this article, a coherent interface between large atomic ensembles and light fields has been proposed to realize quantum memories for light to circumvent the Heisenberg uncertainty principle, which sets a limit on the quality of stored information that depends on direct measurement and subsequent reconstruction.
Abstract: One of the steps toward the realization of quantum computation is a device that allows the coherent storage of information. The Heisenberg uncertainty principle HUP sets a limit on the quality of stored information that depends on direct measurement and subsequent reconstruction. Much experimental and theoretical research is directed toward quantum memories for light to circumvent this classical benchmark. To realize such memories, methods that provide a coherent interface between large atomic ensembles and light fields have been proposed.
TL;DR: A slow light beam splitter using rapid coherence transport in a wall-coated atomic vapor cell that may improve quantum repeater performance and be useful as an all-optical dynamically reconfigurable router.
Abstract: We demonstrate a slow light beam splitter using rapid coherence transport in a wall-coated atomic vapor cell. We show that particles undergoing random and undirected classical motion can mediate coherent interactions between two or more optical modes. Coherence, written into atoms via electromagnetically induced transparency using an input optical signal at one transverse position, spreads out via ballistic atomic motion, is preserved by an antirelaxation wall coating, and is then retrieved in outgoing slow light signals in both the input channel and a spatially-separated second channel. The splitting ratio between the two output channels can be tuned by adjusting the laser power. The slow light beam splitter may improve quantum repeater performance and be useful as an all-optical dynamically reconfigurable router.