Showing papers on "Electromagnetically induced transparency published in 2003"
TL;DR: It is observed that a quantum coherence effect, coherent population oscillations, produces a very narrow spectral "hole" in the homogeneously broadened absorption profile of ruby, which leads to a large value of the group index.
Abstract: We have observed slow light propagation with a group velocity as low as $57.5\ifmmode\pm\else\textpm\fi{}0.5\text{ }\mathrm{m}/\mathrm{s}$ at room temperature in a ruby crystal. A quantum coherence effect, coherent population oscillations, produces a very narrow spectral ``hole'' in the homogeneously broadened absorption profile of ruby. The resulting rapid spectral variation of the refractive index leads to a large value of the group index. We observe slow light propagation both for Gaussian-shaped light pulses and for amplitude modulated optical beams in a system that is much simpler than those previously used for generating slow light.
651 citations
TL;DR: This work describes and experimentally demonstrate a technique in which light propagating in a medium of Rb atoms is converted into an excitation with localized, stationary electromagnetic energy, which can be held and released after a controllable interval, offering new possibilities for photon state manipulation and nonlinear optical processes at low light levels.
Abstract: Physical processes that could facilitate coherent control of light propagation are under active exploration1,2,3,4,5. In addition to their fundamental interest, these efforts are stimulated by practical possibilities, such as the development of a quantum memory for photonic states6,7,8. Controlled localization and storage of photonic pulses may also allow novel approaches to manipulating of light via enhanced nonlinear optical processes9. Recently, electromagnetically induced transparency10 was used to reduce the group velocity of propagating light pulses11,12 and to reversibly map propagating light pulses into stationary spin excitations in atomic media13,14,15,16. Here we describe and experimentally demonstrate a technique in which light propagating in a medium of Rb atoms is converted into an excitation with localized, stationary electromagnetic energy, which can be held and released after a controllable interval. Our method creates pulses of light with stationary envelopes bound to an atomic spin coherence, offering new possibilities for photon state manipulation and nonlinear optical processes at low light levels.
486 citations
TL;DR: The measured Kerr nonlinearity is comparable in magnitude to the linear dispersion in a simple two-level system and is several orders of magnitude greater than the Kerr non linearity of a conventional three-level scheme under similar conditions.
Abstract: We report an experimental observation of large Kerr nonlinearity with vanishing linear susceptibilities in coherently prepared four-level rubidium atoms. Quantum coherence and interference manifested by electromagnetically induced transparency suppress the linear susceptibilities and greatly enhance the nonlinear susceptibilities at low light intensities. The measured Kerr nonlinearity is comparable in magnitude to the linear dispersion in a simple two-level system and is several orders of magnitude greater than the Kerr nonlinearity of a conventional three-level scheme under similar conditions.
397 citations
TL;DR: In this article, a four-wave mixing (FWM) scheme in a five-level atomic system based on electromagnetically induced transparency (EIT) was analyzed.
Abstract: We analyze a four-wave-mixing (FWM) scheme in a five-level atomic system based on electromagnetically induced transparency (EIT). We show that EIT suppresses both two-photon and three-photon absorptions in the FWM scheme and enables the four-wave mixing to proceed through real, resonant intermediate states without absorption loss. The scheme results in a several orders of magnitude increase in the FWM efficiency in comparison with a recent scheme [Phys. Rev. Lett. 88, 143902 (2002)] and may be used for generating short-wavelength radiation at low pump intensities.
381 citations
01 Nov 2003
TL;DR: A theoretical investigation of the criteria for achieving slow light in semiconductor QDs is presented and a compact variable all-optical buffer using semiconductor quantum dot (QD) structures is proposed and analyzed.
Abstract: A compact variable all-optical buffer using semiconductor quantum dot (QD) structures is proposed and analyzed. 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 an electromagnetically induced transparency effect. We present a theoretical investigation of the criteria for achieving slow light in semiconductor QDs. A QD structure in the presence of strain is analyzed with the inclusion of polarization-dependent intersubband dipole selection rules. Experimental methods to synthesize and the measurements of coherent properties in state-of-the-art QDs are surveyed. Slow-light effects in uniform and nonuniform QDs are compared. Finally, optical signal propagation through the semiconductor optical buffer is presented to demonstrate the feasibility for practical applications.
323 citations
TL;DR: In this article, the authors demonstrate a quantum interference switch where a laser pulse with an energy per area of 23$ photons per ${\ensuremath{\sim}23$ photon per ${ \ensuremath{\lambda}}^{2}/(2 \ensureMath{\pi})$ causes a $1/e$ absorption of a second pulse.
Abstract: Electromagnetically induced transparency in an optically thick, cold medium creates a unique system where pulse-propagation velocities may be orders of magnitude less than c and optical nonlinearities become exceedingly large. As a result, nonlinear processes may be efficient at low-light levels. Using an atomic system with three, independent channels, we demonstrate a quantum interference switch where a laser pulse with an energy per area of $\ensuremath{\sim}23$ photons per ${\ensuremath{\lambda}}^{2}/(2\ensuremath{\pi})$ causes a $1/e$ absorption of a second pulse.
221 citations
TL;DR: These studies illustrate that many-particle interactions, which are inherent in semiconductors and are often detrimental to quantum coherences, can also be harnessed to manipulate these coherence levels.
Abstract: We report an experimental demonstration and theoretical analysis of electromagnetically induced transparency in a GaAs quantum well, in which the absorption of an exciton resonance is reduced by more than twentyfold. The destructive quantum interference in this scheme is set up by a control pulse that couples to a resonance of biexcitons. These studies illustrate that many-particle interactions, which are inherent in semiconductors and are often detrimental to quantum coherences, can also be harnessed to manipulate these coherences.
194 citations
TL;DR: In this paper, the optical bistability of an optical ring cavity filled with a collection of three-level $\ensuremath{\Lambda}$-type rubidium atoms, interacting with two collinearly propagating laser beams, was investigated.
Abstract: We have experimentally studied the optical bistable behavior in an optical ring cavity filled with a collection of three-level $\ensuremath{\Lambda}$-type rubidium atoms, interacting with two collinearly propagating laser beams. The bistability so observed is very sensitive to the induced atomic coherence in this electromagnetically induced transparency system or consequently to the altered nonlinearity in the system and, thus, can easily be controlled by changing the intensity and the frequency detuning of the coupling field.
190 citations
TL;DR: Petrosyan and Kurizki as mentioned in this paper proposed a fully quantized model of a double-EIT scheme, based on nonlinear interaction via double EIT of two light fields (initially prepared in coherent states).
Abstract: The generation of an entangled coherent state is one of the most important ingredients of quantum information processing using coherent states. Recently, numerous schemes to achieve this task have been proposed. In order to generate travelling-wave entangled coherent states, cross-phase-modulation, optimized by optical Kerr effect enhancement in a dense medium in an electromagnetically induced transparency (EIT) regime, seems to be very promising. In this scenario, we propose a fully quantized model of a double-EIT scheme recently proposed [D. Petrosyan and G. Kurizki, Phys. Rev. A 65, 33 833 (2002)]: the quantization step is performed adopting a fully Hamiltonian approach. This allows us to write effective equations of motion for two interacting quantum fields of light that show how the dynamics of one field depends on the photon-number operator of the other. The preparation of a Schr\"odinger cat state, which is a superposition of two distinct coherent states, is briefly exposed. This is based on nonlinear interaction via double EIT of two light fields (initially prepared in coherent states) and on a detection step performed using a 50:50 beam splitter and two photodetectors. In order to show the entanglement of an entangled coherent state, we suggest to measure the joint quadrature variance of the field. We show that the entangled coherent states satisfy the sufficient condition for entanglement based on quadrature variance measurement. We also show how robust our scheme is against a low detection efficiency of homodyne detectors.
158 citations
TL;DR: Electromagnetically induced transparency in the transient optical response in a GaAs quantum well is demonstrated by using the nonradiative coherence between the heavy-hole and the light-hole valence bands.
Abstract: We demonstrate electromagnetically induced transparency in the transient optical response in a GaAs quantum well by using the nonradiative coherence between the heavy-hole and the light-hole valence bands
158 citations
TL;DR: A hyper-Raman scheme for generation of coherent light in a five-level atomic system based on electromagnetically induced transparency (EIT) is proposed and it is shown that EIT suppresses linear and nonlinear photon absorption and enables the hyper- Raman process to proceed through real, near-resonant intermediate states.
Abstract: We propose and analyze a hyper-Raman scheme for generation of coherent light in a five-level atomic system based on electromagnetically induced transparency (EIT). We show that EIT suppresses linear and nonlinear photon absorption and enables the hyper-Raman process to proceed through real, near-resonant intermediate states. The scheme greatly enhances hyper-Raman efficiency and may be used for generating short-wavelength radiation at low pump intensities.
TL;DR: In this article, the authors present a method to generate continuous variable-type entangled states between photons and atoms in atomic Bose-Einstein condensate (BEC) systems with three internal states, a weak quantized probe laser, and a strong classical coupling laser.
Abstract: In this paper, we present a method to generate continuous-variable-type entangled states between photons and atoms in atomic Bose-Einstein condensate (BEC). The proposed method involves an atomic BEC with three internal states, a weak quantized probe laser, and a strong classical coupling laser, which form a three-level $\ensuremath{\Lambda}$-shaped BEC system. We consider a situation where the BEC is in electromagnetically induced transparency with the coupling laser being much stronger than the probe laser. In this case, the upper and intermediate levels are unpopulated, so that their adiabatic elimination enables an effective two-mode model involving only the atomic field at the lowest internal level and the quantized probe laser field. Atom-photon quantum entanglement is created through laser-atom and interatomic interactions, and two-photon detuning. We show how to generate atom-photon entangled coherent states and entangled states between photon (atom) coherent states and atom-(photon-) macroscopic quantum superposition (MQS) states, and between photon-MQS and atom-MQS states.
TL;DR: It is shown experimentally and theoretically that photorefractive wave coupling can be used for dramatic (< or approximately 0.025 cm/s) deceleration of light pulses whose width is larger than (or comparable with) the nonlinear response time.
Abstract: It is shown experimentally and theoretically that photorefractive wave coupling can be used for dramatic ($\ensuremath{\lesssim}0.025\text{ }\mathrm{c}\mathrm{m}/\mathrm{s}$) deceleration of light pulses whose width is larger than (or comparable with) the nonlinear response time. This classical nonlinear scheme exhibits similarities with the technique based on the quantum effect of electromagnetically induced transparency. The main distinctive feature of our scheme is amplification of the delayed output pulse. Advantages of the novel technique and its prospects for manipulation with light photons are discussed.
TL;DR: In this paper, quantum-coherence phenomena in a semiconductor quantum-dot structure were explored and the authors predicted the occurrence of inversionless gain, electromagnetically induced transparency, and refractive index enhancement in the transient regime for dephasing rates typical under room temperature and high excitation conditions.
Abstract: This paper explores quantum-coherence phenomena in a semiconductor quantum-dot structure. The calculations predict the occurrence of inversionless gain, electromagnetically induced transparency, and refractive-index enhancement in the transient regime for dephasing rates typical under room temperature and high excitation conditions. They also indicate deviations from atomic systems because of strong many-body effects. Specifically, Coulomb interaction involving states of the quantum dots and the continuum belonging to the surrounding quantum well leads to collision-induced population redistribution and many-body energy and field renormalizations that modify the magnitude, spectral shape, and time dependence of quantum-coherence effects.
TL;DR: In this paper, the authors show that the high phase velocity in the slow light regime ensures that the system cannot be used as an analogue displaying Hawking radiation, and that even though an appropriately designed slow-light setup may simulate classical features of black holes, it does not reproduce the related quantum effects.
Abstract: Although slow light (electromagnetically induced transparency) would seem an ideal medium in which to institute a ``dumb hole'' (black hole analogue), it suffers from a number of problems. We show that the high phase velocity in the slow light regime ensures that the system cannot be used as an analogue displaying Hawking radiation. Even though an appropriately designed slow-light setup may simulate classical features of black holes---such as horizon, mode mixing, ``Bogoliubov'' coefficients, etc.---it does not reproduce the related quantum effects.
TL;DR: In this paper, double dark resonances originate from a coherent perturbation of a system displaying electromagnetically induced transparency, where the magnetic coupling between the Zeeman levels leads to nonlinear generation of a comb of sidebands.
Abstract: Double dark resonances originate from a coherent perturbation of a system displaying electromagnetically induced transparency. We experimentally show and theoretically confirm that this leads to the possibility of extremely sharp resonances prevailing even in the presence of considerable Doppler broadening. A gas of ${}^{87}\mathrm{Rb}$ atoms is subjected to a strong drive laser and a weak probe laser and a radio frequency field, where the magnetic coupling between the Zeeman levels leads to nonlinear generation of a comb of sidebands.
TL;DR: In this article, the authors compared methods of active stabilization of an optoelectronic microwave oscillator (OEO) based on insertion of a source of optical group delay into an OEO loop.
Abstract: This paper compares methods of active stabilization of an optoelectronic microwave oscillator (OEO) based on insertion of a source of optical group delay into an OEO loop. The performance of an OEO stabilized with either a high-Q optical cavity or an atomic cell is analyzed. We show that the elements play a role of narrow-band microwave filters improving an OEO stability. An atomic cell also allows for locking the oscillation frequency to particular atomic clock transitions. This reports a proof-of-principle experiment on an OEO stabilization using the effect of electromagnetically induced transparency in a hot rubidium atomic vapor cell.
TL;DR: In this paper, a three-level atomic system coupled by two equal-amplitude laser fields with a frequency separation 2delta was investigated, where a weak probe field exhibits a multiple-peaked absorption spectrum with a constant peak separation delta, which leads to simultaneous slow group velocities for probe photons at multiple frequencies separated by delta.
Abstract: In a three-level atomic system coupled by two equal-amplitude laser fields with a frequency separation 2delta, a weak probe field exhibits a multiple-peaked absorption spectrum with a constant peak separation delta. The corresponding probe dispersion exhibits steep normal dispersion near the minimum absorption between the multiple absorption peaks, which leads to simultaneous slow group velocities for probe photons at multiple frequencies separated by delta. We report an experimental study in such a bichromatically coupled three-level Lambda system in cold Rb-87 atoms. The multiple-peaked probe absorption spectra under various experimental conditions have been observed and compared with the theoretical calculations. (C) 2003 American Institute of Physics.
TL;DR: In this paper, a four-level atomic system in inverted-Y configuration is considered and the phenomenon of electromagnetically induced transparency (EIT) in this system under various parametric conditions in order to demonstrate controllability of the EIT and its dispersion properties.
TL;DR: In this paper, a weak probe light beam can form spatial solitons in an electromagnetically induced transparency (EIT) medium composed of four-level atoms and a coupling light field.
Abstract: We show that a weak probe light beam can form spatial solitons in an electromagnetically induced transparency (EIT) medium composed of four-level atoms and a coupling light field. We find that the coupling light beam can induce a highly controllable nonlinear waveguide and exert very strong effects on the dynamical behavior of the solitons. Hence, in the EIT medium, it is not only possible to produce spatial solitons at very low light intensities but also simultaneously control these solitons by using the coupling-light-induced nonlinear waveguide.
TL;DR: In this paper, it was shown that in a four-level atomic system with electromagnetically induced transparency, a coherent pump field can induce light amplification without or with population inversion.
Abstract: We show that in a four-level atomic system with electromagnetically induced transparency, a coherent pump field can induce light amplification without or with population inversion. As the pump field intensity increases, the atomic system evolves from normal dispersion and amplification without population inversion into anomalous dispersion and amplification with population inversion. We report an experiment on light amplification in cold rubidium atoms and present experimental measurements that agree with theoretical calculations based on the four-level model system.
TL;DR: In this article, the dependence of the transmission linewidth on the driving field intensity is discussed and compared to the laser-induced line-narrowing effect in high resolution spectroscopy based on electromagnetically induced transparency.
Abstract: The laser-induced line-narrowing effect, discovered more than thirty years ago, can also be applied to recent studies in high resolution spectroscopy based on electromagnetically induced transparency. In this paper we first present a general form of the transmission width of electromagnetically induced transparency in a homogeneously broadened medium. We then analyze a Doppler broadened medium by using a lorentzian function as the atomic velocity distribution. The dependence of the transmission linewidth on the driving field intensity is discussed and compared to the laser-induced line-narrowing effect. This dependence can be characterized by a parameter which can be regarded as “the degree of optical pumping.”
TL;DR: A dual electromagnetically induced transparency (EIT) based multiwave mixing scheme that retains the significantly enhanced conversion efficiency enabled by ultraslow propagation of pump waves, yet is also capable of inhibiting and delaying the onset of the detrimental three-photon destructive interference that limits the further growth of the four-wave mixing (FWM) field.
Abstract: We propose a dual electromagnetically induced transparency (EIT) based multiwave mixing scheme that retains the significantly enhanced conversion efficiency enabled by ultraslow propagation of pump waves, yet is also capable of inhibiting and delaying the onset of the detrimental three-photon destructive interference that limits the further growth of the four-wave mixing (FWM) field. We show that the new scheme exhibits a wave-matching condition that is fundamentally different from the conventional FWM without EIT, and the efficient generation of the mixing wave is not critically dependent upon the FWM detuning to achieve constructive interference as required in the conventional FWM. These are significant steps forward in enabling applications of ultraslow wave nonlinear optics.
TL;DR: In this article, the intensity fluctuations of pump and probe beams after interaction with Rb atoms in a situation of Electromagnetically Induced Transparency were measured, in good qualitative agreement with theoretical predictions in which both fields are treated quantum-mechanically.
Abstract: We have measured the intensity fluctuations of pump and probe beams after interaction with Rb atoms in a situation of Electromagnetically Induced Transparency. Both fields present super-Poissonian statistics and their intensities become correlated, in good qualitative agreement with theoretical predictions in which both fields are treated quantum-mechanically. The intensity correlations measured are a first step towards the observation of entanglement between the fields.
TL;DR: A novel scheme to realize electromagnetically induced transparency (EIT) via robust electron spin coherence in semiconductor quantum wells using light hole transitions in a quantum well waveguide to induce electron Spin Coherence in the absence of an external magnetic field is proposed.
Abstract: We propose and analyze a novel scheme to realize electromagnetically induced transparency (EIT) via robust electron spin coherence in semiconductor quantum wells. This scheme uses light hole transitions in a quantum well waveguide to induce electron spin coherence in the absence of an external magnetic field. For certain polarization configurations, the light hole transitions form a crossed double-V system. EIT in this system is strongly modified by a coherent wave mixing process induced by the electron spin coherence.
TL;DR: In this paper, a light beam normally incident upon an uniformly moving dielectric medium is, in general, subject to bendings due to a transverse Fresnel-Fizeau light drag effect.
Abstract: A light beam normally incident upon an uniformly moving dielectric medium is, in general, subject to bendings due to a transverse Fresnel-Fizeau light drag effect. In most familiar dielectrics, the magnitude of this bending effect is very small and hard to detect. Yet, the effect can be dramatically enhanced in strongly dispersive media where slow group velocities in the m/s range have been recently observed taking advantage of the electromagnetically induced transparency effect. In addition to the usual downstream drag that takes place for positive group velocities, we discuss a significant anomalous upstream drag which is expected to occur for negative group velocities. Furthermore, for sufficiently fast speeds of the medium, higher-order dispersion terms are found to play an important role and to be responsible for light propagation along curved paths or the restoration of the time and space coherence of an incident noisy beam. The physics underlying this class of slow-light effects is thoroughly discussed.
TL;DR: In this paper, an integrated optics directional coupler filter based on coupling between a regular waveguide and one that exhibits electromagnetically induced transparency was proposed. But the operation of the filter was not discussed.
Abstract: We describe the principle and analyze the operation of an integrated optics directional coupler filter based on coupling between a regular waveguide and one that exhibits electromagnetically induced transparency. Bandwidth length products on the order of 2 pm /spl times/ mm are obtainable, as an example, using this approach.
TL;DR: A new approach to fast optical switching with a technique based on stimulated Raman adiabatic passage in which a laser pulse switches the probe field on and off via another coupling pulse that can operate in the subnanosecond time domain.
Abstract: We demonstrate a new approach to fast optical switching with a technique based on stimulated Raman adiabatic passage in which a laser pulse switches the probe field on and off via another coupling pulse. This new kind of optical switching is not limited by the decay rate of an excited state and can operate in the subnanosecond time domain. The experimental observation in Rb atomic vapor is in good agreement with numerical simulations.
TL;DR: In this article, the authors generalize the Lambda system by introducing further degenerate states to realize a ''chain $\ensuremath{\Lambda}'' atom where multiple coupling of the probe field significantly enhances the intensity-dependent dispersion without compromising the EIT condition.
Abstract: Interest in lossless nonlinearities has focussed on the dispersive properties of $\ensuremath{\Lambda}$ systems under conditions of electromagnetically induced transparency (EIT). We generalize the $\ensuremath{\Lambda}$ system by introducing further degenerate states to realize a ``chain $\ensuremath{\Lambda}''$ atom where multiple coupling of the probe field significantly enhances the intensity-dependent dispersion without compromising the EIT condition.
TL;DR: In this article, the results of a pump-probe laser spectroscopic investigation of the Doppler-broadened sodium $D1$ resonance line were presented, and the authors found 13 resonances in the resulting spectra.
Abstract: We present the results of a pump-probe laser spectroscopic investigation of the Doppler-broadened sodium $D1$ resonance line. We find 13 resonances in the resulting spectra. These observations are well described by the numerical predictions of a four-level atomic model of the hyperfine structure of the sodium $D1$ line. We also find that many, but not all, of these features can be understood in terms of processes originating in a two-level or three-level subset of the full four-level model. The processes we observed include forward near-degenerate four-wave mixing and saturation in a two-level system, difference-frequency crossing and nondegenerate four-wave mixing in a three-level V system, electromagnetically induced transparency and optical pumping in a three-level lambda system, cross-transition resonance in a four-level double-lambda system, and conventional optical pumping. Most of these processes lead to sub-Doppler or even subnatural linewidths. The dependence of these resonances on the pump intensity and pump detuning from atomic resonance are also studied.