Showing papers on "Electromagnetically induced transparency published in 1999"
TL;DR: In this paper, an experimental demonstration of electromagnetically induced transparency in an ultracold gas of sodium atoms, in which the optical pulses propagate at twenty million times slower than the speed of light in a vacuum, is presented.
Abstract: Techniques that use quantum interference effects are being actively investigated to manipulate the optical properties of quantum systems1. One such example is electromagnetically induced transparency, a quantum effect that permits the propagation of light pulses through an otherwise opaque medium2,3,4,5. Here we report an experimental demonstration of electromagnetically induced transparency in an ultracold gas of sodium atoms, in which the optical pulses propagate at twenty million times slower than the speed of light in a vacuum. The gas is cooled to nanokelvin temperatures by laser and evaporative cooling6,7,8,9,10. The quantum interference controlling the optical properties of the medium is set up by a ‘coupling’ laser beam propagating at a right angle to the pulsed ‘probe’ beam. At nanokelvin temperatures, the variation of refractive index with probe frequency can be made very steep. In conjunction with the high atomic density, this results in the exceptionally low light speeds observed. By cooling the cloud below the transition temperature for Bose–Einstein condensation11,12,13 (causing a macroscopic population of alkali atoms in the quantum ground state of the confining potential), we observe even lower pulse propagation velocities (17?m?s−1) owing to the increased atom density. We report an inferred nonlinear refractive index of 0.18?cm2?W−1 and find that the system shows exceptionally large optical nonlinearities, which are of potential fundamental and technological interest for quantum optics.
3,438 citations
TL;DR: In this article, the combination of electromagnetically induced transparency based nonlinear optics and cold atom technology, under conditions of ultra-low light propagation, allows nonlinear processes at energies of a few photons per atomic cross section.
Abstract: We show how the combination of electromagnetically induced transparency based nonlinear optics and cold atom technology, under conditions of ultraslow light propagation, allows nonlinear processes at energies of a few photons per atomic cross section.
711 citations
TL;DR: In this paper, the authors investigated the dynamics of light propagation in a cell with antirelaxation wall coating and found that the observed dynamics are analogous to those in electromagnetically induced transparency.
Abstract: The dynamics of resonant light propagation in rubidium vapor in a cell with antirelaxation wall coating are investigated. We change the polarization of the input light and measure the time dependence of the polarization after the cell. The observed dynamics are shown to be analogous to those in electromagnetically induced transparency. Spectral dependence of light pulse delays is found to be similar to that of nonlinear magneto-optic rotation. Delays up to [approx]13 ms are observed, corresponding to a 8 m/s group velocity. Fields of a few microgauss are used to control the group velocity. [copyright] [ital 1999] [ital The American Physical Society ]
508 citations
TL;DR: In this article, the authors predict the possibility of sharp, high contrast resonances in the optical response of a broad class of systems, wherein interference effects are generated by coherent perturbation or interaction of dark states.
Abstract: We predict the possibility of sharp, high-contrast resonances in the optical response of a broad class of systems, wherein interference effects are generated by coherent perturbation or interaction of dark states. The properties of these resonances can be manipulated to design a desired atomic response.
279 citations
TL;DR: In this article, the authors observed diffraction signals by a grating originating from electromagnetically induced transparency (EIT) in a three-level \ensuremath{\Lambda} system of cold sodium atoms.
Abstract: We have observed diffraction signals by a grating originating from electromagnetically induced transparency (EIT) in a three-level \ensuremath{\Lambda} system of cold sodium atoms. Theoretical and experimental analyses of this phenomenon, called the electromagnetically induced grating (EIG), have revealed that EIG spectra exhibit background-free, Lorentzian signal profiles regardless of the pump frequencies, making a clear contrast to the case of ordinary EIT spectra.
155 citations
TL;DR: In this paper, the experimental demonstration of phase-dependent electromagnetically induced transparency (EIT) is presented, which is based on a quantum interference in closed-loop schemes of interaction of atoms with the radiation.
Abstract: We report on the experimental demonstration of phase-dependent electromagnetically induced transparency (EIT). This effect is based on a quantum interference in closed-loop schemes of interaction of atoms with the radiation. It allows us to control optical properties of the medium by the phases of the laser fields. We discuss some of the possible applications of phase-dependent EIT.
144 citations
TL;DR: In this article, the Coulomb interaction between electrons was studied in the presence of tunneling induced Fano interference in semiconductor quantum wells, and the authors showed that for a small subband dispersion, gain or loss was determined by single-electron Fano interferences.
Abstract: Absorption cancellation via tunneling induced Fano interference in semiconductor quantum wells is studied in the presence of the Coulomb interaction between electrons. For a small subband dispersion, gain or loss is determined by single-electron Fano interference. For a large subband dispersion, collective excitations dominate the absorption spectrum and are crucial for the observability of tunneling induced transparency, which exists in spite of subband dispersion. Pumping destroys collective excitations; therefore gain without inversion is possible only for small subband dispersion.
136 citations
TL;DR: In this article, a photon blockade effect is inferred to occur for both single and multi-atom cases from the behavior of transition rates between dressed states of the system, and numerical calculations of the second-order coherence function indicate that photon antibunching in both single- and two-atom case are strong and comparable.
Abstract: Dissipation-free photon-photon interaction at the single-photon level is studied in the context of cavity electromagnetically induced transparency (EIT). For a single multilevel atom exhibiting EIT in the strong cavity-coupling regime, the anharmonicity of the atom-cavity system has an upper bound determined by single atom-photon coupling strength. A photon blockade effect is inferred to occur for both single- and multiatom cases from the behavior of transition rates between dressed states of the system. Numerical calculations of the second-order coherence function indicate that photon antibunching in both single- and two-atom cases are strong and comparable.
128 citations
TL;DR: In this paper, it was shown that by the application of an additional driving field, the sharp EIT feature can be split into a doublet or a triplet depending on the experimental configuration.
Abstract: Using electron-spin-resonance transitions within the nitrogen-vacancy center in diamond, we have obtained a sharp electromagnetically induced transparency (EIT) feature when the coupling and probing fields satisfy a two-photon resonance condition. In this paper it is shown that by the application of an additional driving field the sharp EIT feature can be split into a doublet or a triplet depending on the experimental configuration. The results are interpreted in terms of dynamic Stark splitting of the EIT feature, and the spectra are shown to be related to Autler-Townes and Mollow spectra.
71 citations
TL;DR: In this paper, the authors proposed a scheme to generate a large Kerr nonlinearity based on electromagnetically induced transparency in a single atom placed in a high-finesse microcavity.
Abstract: We propose a scheme to generate a large Kerr nonlinearity based on electromagnetically induced transparency in a single atom placed in a high-finesse microcavity. We perform a thorough analysis of the system dynamics using a dressed states approach. This system is shown to create a photon blockade effect equivalent to that for an ideal Kerr nonlinearity as recently proposed by Imamoglu et al 1997 Phys. Rev. Lett. 79 1467.
60 citations
TL;DR: In this article, the effects of mismatching wavelengths for the coupling and probe fields in Doppler-broadened media for the three basic energy level configurations commonly used to realize electromagnetically induced transparency (EIT) were considered.
Abstract: We present a theoretical study of the effects of mismatching wavelengths for the coupling and probe fields in Doppler-broadened media for the three basic energy level configurations commonly used to realize electromagnetically induced transparency (EIT). Three wavelength regimes are considered: mismatched wavelengths for which the coupling frequency is greater than the probe frequency, matched wavelengths for which the coupling and probe frequencies are equal, and mismatched wavelengths for which the probe frequency is greater than the coupling frequency. The transparency that may be induced in these regimes is compared for the cascade-, \ensuremath{\Lambda}-, and Vee-type systems. We show that in the first mismatched regime $({\ensuremath{\lambda}}_{c}l{\ensuremath{\lambda}}_{p})$ EIT is possible in all schemes and is in fact stronger than in the matched case. It is also demonstrated that for the second mismatched regime $({\ensuremath{\lambda}}_{c}g{\ensuremath{\lambda}}_{p})$ EIT can be realized most readily in the Vee-type configuration in the presence of Doppler broadening. These predictions are explained by considering the absorption as a function of both the probe field detuning and the atomic velocity.
TL;DR: In this article, a four-level atom driven by two coherent fields is studied and it is shown that when one of the driving fields is tuned at the middle point of the upper levels, the dipole moments between the two upper levels and each of the two lower levels are parallel, the spontaneous emission paths from the upper level to the lower levels will have strongly or even completely destructive quantum interference.
Abstract: The resonance fluorescence from a four-level atom driven by two coherent fields is studied. If the dipole moments between the two upper levels and each of the two lower levels are parallel, the spontaneous emission paths from the upper levels to the lower levels will have strongly or even completely destructive quantum interference. We show that this quantum interference will result in a complete inhibition of the fluorescence when one of the driving fields is tuned at the middle point of the upper levels. The quantum interference will lead to the dependence of atomic populations at steady state on the initial condition, when both of the driving fields are tuned to the middle point of the upper levels. When the dipole moments are close to but not exactly parallel, or none of the driving fields is tuned at the middle point of the upper levels and there is a small difference between detunings of the two driving fields to the uppermost level, ultranarrow lines at the spectral center appear because of the destructive quantum interference.
TL;DR: In this paper, a sharp transparency feature is induced in an allowed electron spin resonance (ESR) transition by driving a nominally spin-forbidden transition, which is interpreted as being associated with electromagnetically induced transparency (EIT).
Abstract: A sharp transparency feature is induced in an allowed electron spin resonance (ESR) transition by driving a nominally spin-forbidden transition. The width of the feature is narrower than the homogeneous linewidth of the ESR transition and is interpreted as being associated with electromagnetically induced transparency (EIT). Measurements are made for the nitrogen-vacancy centre in diamond and the signals are detected using a coherent optical technique.
TL;DR: It is shown that STIRAP is the underlying physical mechanism for electromagnetically induced transparency (EIT), and in optically thick media coherent-state preparation is only possible by entirely coherent means such as stimulated Raman adiabatic passage.
Abstract: The preparation of an optically dense ensemble of three-level systems in dark states of the interaction with coherent radiation is discussed. It is shown that methods involving spontaneous emissions of photons such as Raman optical pumping fail to work beyond a critical density due to multiple scattering and trapping of these photons and the associated decay of the dark state(s). In optically thick media coherent-state preparation is only possible by entirely coherent means such as stimulated Raman adiabatic passage (STIRAP). It is shown that STIRAP is the underlying physical mechanism for electromagnetically induced transparency (EIT).
TL;DR: In this paper, the spectral position of the absorption minimum in a coherent population trapping resonance in thermal cesium vapor was measured as a function of light intensity and the dependence of position on intensity was found to be almost linear.
Abstract: We have measured the spectral position of the absorption minimum in a coherent population trapping resonance in thermal cesium vapor as a function of light intensity. The dependence of position on intensity is found to be almost linear. We have furthermore studied the dependence of this light shift on neon buffer gas pressure and find a strong reduction for higher pressures. So the addition of a buffer gas not only reduces the linewidth of the resonance but also a very important systematic effect for precision measurements.
TL;DR: In this paper, the authors studied the effect of Fano interference on the propagation of a short laser pulse in an autoionizing medium and derived the Maxwell-Bloch equations for the pulse propagation.
Abstract: The study of the propagation of electromagnetic pulses in multi-level media has lead to the discovery of a number of interesting phenomena. These include the simultaneous propagation of two pulses having different fundamental frequencies ~‘‘simultons’’ !@ 1,2#, electromagnetically induced transparency under matched pulse conditions @3‐7# and the creation and propagation of ‘‘adiabatons,’’ a general class of pulses which show solitonic behavior in adiabatically evolving atomic systems @8‐11#. Pulse propagation effects have also been investigated within other contexts. Examples include the study of lasing without population inversion @12#, the influence of the quantized nature of laser fields @13,14#, ‘‘dragging and cloning’’ of laser pulses @15#, the effects of initial superpositions of the atomic states @16,17#, and the effects of Doppler broadening @18#. Furthermore, systems where a spatial excitation can be controlled @19# or even imaged in the temporal profile of laser pulses@20# have been discussed. In these studies, systems involving bound states were considered. The introduction of dissipative processes are detrimental to, and can even destroy, the coherence required for the manifestation of the above mentioned phenomena. However, recently it has been shown that, using the laser-induced continuum structure ~LICS! scheme @21,22#, atomic coherence can be preserved even in systems in which dissipative processes ~e.g., ionization! are present. These latter studies utilize two lasers in a probe-coupling configuration. Interfering processes arising from the coherent laser-matter interaction involving both of these lasers are necessary for transparency or solitonlike propagation in the medium. In this paper, we investigate the propagation dynamics of a short laser pulse interacting with an autoionizing medium. We show that Fano interference @23# can lead to transparency in the medium, thereby allowing the laser pulse to propagate without absorption. This phenomenon is closely related to the transparency predicted in a four-level medium via spontaneous-emission interference @24#. The essential feature of the present system is the presence of a continuum of atomic states, so that dissipation is intrinsic to the system. However, the decay processes can interfere and this can give rise to transparency in the medium, as will be discussed below. In contrast to the LICS scheme @21,22#, here only a single laser, the probe laser that couples the ground state to both the autoionizing state and the continuum, is involved. The configuration interaction which couples the autoionizing state to the continuum is responsible for the necessary interference in this case, rather than a second laser field. Since Fano’s original work, a number of studies have considered the total absorption of a laser field in the autoionizing medium in the weak-field limit @25#. Numerical studies of the Maxwell-Bloch equations for the pulse propagation have also been carried out @26#. In this article, we re-examine short laser pulse propagation in an autoionizing medium. We place emphasis on establishing the connection between adiabatic population trapping in short, pulsed laser fields @27,28# and transparency in the propagation of the laser pulse in the medium. Furthermore, we calculate both analytically and numerically corrections to the adiabatic behavior and show that in the first approximation the laser pulse retains its shape and only its group velocity is modified. In the following section we derive the Maxwell‘ ‘
Book•
15 Aug 1999
TL;DR: In this paper, the authors present experiments in EIT and LWI in Semiconductors, where the EIT is used to measure the properties of the laser light properties.
Abstract: Classical Physics - Basics Non-Linear Optics - Basics Quantum Physics - Basics Coherent States and Properties of Laser Light Two-Level Systems Three-Level Systems Atomic Interference and Coherence Experiments in EIT Experiments in LWI LWI and EIT in Semiconductors 1 LWI and EIT in Semiconductors 2 and Outlook Appendix Exercises and Problems
TL;DR: In this article, the authors observed electromagnetically induced transparency (EIT) in rare earth Pr3+-doped Y2SiO5 over the spectral hole-burning temperature.
Abstract: We have observed electromagnetically induced transparency (EIT) in rare-earth Pr3+-doped Y2SiO5 over the spectral hole-burning temperature. The transmission of the probe laser beam is increased by a factor of exp(1.4) at 12 K when a coupling laser of 1.2 kW/cm2 is applied to the system. The observation of EIT over the spectral hole-burning temperature in a rare-earth–doped solid represents important progress toward high-density echo-based optical memories at higher temperatures.
TL;DR: In this paper, the authors consider the possibility of wave propagation in the normally disallowed (band-gap) region of a resonant optical medium, that is, in the band of frequencies near resonance where the real part of the frequency-dependent dielectric function is negative.
Abstract: We consider the possibility of wave propagation in the normally disallowed (band-gap) region of a resonant optical medium, that is, in the band of frequencies near resonance where the real part of the frequency-dependent dielectric function is negative. We demonstrate that wave propagation can become allowed by the application of a strong electromagnetic field resonant with some additional transition of the material system. The frequencies at which these effects can occur are strongly influenced by local-field effects.
TL;DR: In this article, it is shown that it is possible to store quantum states of single-photon fields by mapping them onto meta-stable states of an optically dense, coherently driven medium inside an optical resonator.
Abstract: We show that it is possible to ``store'' quantum states of single-photon fields by mapping them onto {\it collective} meta-stable states of an optically dense, coherently driven medium inside an optical resonator. An adiabatic technique is suggested which allows to transfer non-classical correlations from traveling-wave single-photon wave-packets into atomic states and vise versa with nearly 100% efficiency. In contrast to previous approaches involving single atoms, the present technique does not require the strong coupling regime corresponding to high-Q micro-cavities. Instead, intracavity Electromagnetically Induced Transparency is used to achieve a strong coupling between the cavity mode and the atoms.
Journal Article•
TL;DR: In this article, the temporal behavior of a three-level system, initially prepared in an excited state, bathed in a laser field tuned at the transition frequency of the other level, was analyzed.
Abstract: We study the temporal behavior of a three-level system (such as an atom or a molecule), initially prepared in an excited state, bathed in a laser field tuned at the transition frequency of the other level. We analyze the dependence of the lifetime of the initial state on the intensity of the laser field. The phenomenon we discuss is related to both electromagnetic induced transparency and quantum Zeno effect.
01 Jan 1999
TL;DR: In this paper, a review of theoretical and experimental evidence for quantum interference in intersub-band transitions of coupled semiconductor quantum wells is presented, and it is shown that quantum interference occurs between the levels of these collective intersubband excitations rather than single electronic states.
Abstract: We present a review of theoretical and experimental evidence for quantum interference in intersub- band transitions of coupled semiconductor quantum wells. Intersubband absorption spectra are calculated using semiconductor Bloch equations to include the Coulomb interaction between the conduction band electrons. We demonstrate that the absorption spectra must be viewed as collective excitations. In a configuration analogous to electromagnetically induced transparency (EIT) in atomic systems, we show that quantum interference occurs between the levels of these collective intersubband excitations rather than single electronic states. Exper- iments which demonstrate quantum interference in coupled quantum wells due to tunneling induced transpar- ency (TIT) are presented. The design issues for such samples are reviewed, and the effects of monolayer growth fluctuations on the spectra are simulated. Finally, we discuss the temperature dependence of TIT and demon- strate that the quantum interference persists at room temperature.
TL;DR: A simple physical analysis in terms of modification of the frequency-correlation factor for cascade and multiphoton processes in strong driving fields is developed in this article, where the possibilities of elimination of Doppler broadening by making use of atomic coherence in ladder-and folded-type configurations of quantum transitions are considered.
Abstract: Possibilities of elimination of Doppler broadening by making use of atomic coherence in ladder- and folded-type configurations of quantum transitions are considered. A simple physical analysis in terms of modification of the frequency-correlation factor for cascade and multiphoton processes in strong driving fields is developed.
TL;DR: In this article, the frequencies of two laser pairs were adjusted to coincide with the centers of gravity of two hyperfine split transitions to obtain electromagnetically induced transparency, where no hyperfine states are in Raman resonance and the zero of the dipole moment results from interference of the manifold of cooperating m states.
Abstract: We describe a method and present experimental results for obtaining electromagnetically induced transparency by adjusting the frequencies of two lasers so that they coincide with the centers of gravity of two hyperfine split transitions. No hyperfine states are in Raman resonance and the zero of the dipole moment results from the interference of the manifold of cooperating m states.
TL;DR: In this article, the authors proposed an alternative method to Q switching for generating giant pulses of laser light in three-level media based on the presence of an external coherent field driving one transition to allow the accumulation of a large population inversion in the other transition without laser oscillation even in a cavity with high Q$ factor.
Abstract: We propose an alternative method to Q switching for generating giant pulses of laser light in three-level media. This mehod is based on the presence of an external coherent field driving one transition to allow the accumulation of a large population inversion in the other transition without laser oscillation even in a cavity with high-$Q$ factor. The switching off of the external coherent field causes the development of the giant pulse. Different time profiles for the switching off of the external field have been investigated.
TL;DR: In this article, a description of the second-order nonlinear optical susceptibility of semiconductor materials is considered, where the Lie algebra su(3) arises from a 3-level quantum model for each state in the Brillouin zone, which is obtained by truncation of the true infinite-dimensional basis.
Abstract: A description of the second–order nonlinear optical susceptibility of semiconductor materials is considered. The Lie algebra su(3) arises from a 3–level quantum model for each state in the Brillouin zone, which is obtained by truncation of the true infinite–dimensional basis. The accuracy of several approximations inherent in this approach is analysed, in particular the electric dipole and minimal replacement Hamiltonians which specify the electrodynainical interaction in a finite–dimensional quantum system. The three–level model is extended by adding relaxation processes and utilising the rotating wave approximation to account for resonant nonlinear effects. Analytical forms for the transition rates associated with two–photon absorption and electromagnetically induced transparency are derived.