Showing papers on "Electromagnetically induced transparency published in 2007"
TL;DR: It is shown that the EIT spectra allow direct optical detection of electric field transients in the gas phase, and measurements of the fine structure splitting of the nd series up to n=96 are extended.
Abstract: We demonstrate coherent optical detection of highly excited Rydberg states (up to n=124) using electromagnetically induced transparency (EIT), providing a direct nondestructive probe of Rydberg energy levels. We show that the EIT spectra allow direct optical detection of electric field transients in the gas phase, and we extend measurements of the fine structure splitting of the nd series up to n=96. Coherent coupling of Rydberg states via EIT could also be used for cross-phase modulation and photon entanglement.
520 citations
TL;DR: In this article, the authors performed optical pulse propagation experiments in a system in which two ultrahigh-Q silica microspheres of different diameters were coupled in tandem to a fiber taper to yield coupled-resonator-induced transparency.
Abstract: We performed optical pulse propagation experiments in a system in which two ultrahigh-Q silica microspheres of different diameters were coupled in tandem to a fiber taper to yield coupled-resonator-induced transparency. Nearly Gaussian-shaped optical pulses propagated with a large positive delay of 8.5 ns through a transparent frequency window, without significant attenuation, amplification, or pulse deformation, demonstrating classical analogy of the extremely slow light obtained with electromagnetically induced transparency.
412 citations
TL;DR: In this paper, the authors reported the first demonstration of storing light using photonic structures on-chip, with storage times longer than the bandwidth-determined photon lifetime of the static device.
Abstract: Storing light on-chip, which requires that the speed of light be significantly slowed down, is crucial for enabling photonic circuits on-chip. Ultraslow propagation1,2,3 and even stopping4,5 of light have been demonstrated using the electromagnetically induced transparency effect in atomic systems1,3,4,5 and the coherent population oscillation effect in solid-state systems2. The wavelengths and bandwidths of light in such devices are tightly constrained by the property of the material absorption lines, which limits their application in information technologies. Various slow-light devices based on photonic structures have also been demonstrated6,7,8,9,10; however, these devices suffer a fundamental trade-off between the transmission bandwidth and the optical delay. It has been shown theoretically11,12,13 that stopping light on-chip and thereby breaking the fundamental link between the delay and the bandwidth can be achieved by ultrafast tuning of photonic structures. Using this mechanism, here we report the first demonstration of storing light using photonic structures on-chip, with storage times longer than the bandwidth-determined photon lifetime of the static device. The release time of the pulse is externally controlled.
326 citations
TL;DR: The simultaneously opened dual electromagnetically induced transparency windows in this four-level atomic system allow observation of these two nonlinear optical processes at the same time, which enables detailed studies of the interplay between the FWM and SWM processes.
Abstract: Highly efficient four-wave mixing (FWM) and six-wave mixing (SWM) processes can coexist in a four-level Y-type atomic system due to atomic coherence The simultaneously opened dual electromagnetically induced transparency windows in this four-level atomic system allow observation of these two nonlinear optical processes at the same time, which enables detailed studies of the interplay between the FWM and SWM processes Three-photon and five-photon destructive interferences are also observed
267 citations
TL;DR: In this article, the formation of microwave solitons in a crystal of molecular magnets via an electromagnetically induced transparency and the giant cross-phase modulation phase shifts with the advantages of low pump powers, low absorptions, high sensitivities, and certain frequency tunability.
Abstract: The authors show the formation of microwave solitons in a crystal of molecular magnets via an electromagnetically induced transparency and have the giant cross-phase modulation phase shifts with the advantages of low pump powers, low absorptions, high sensitivities, and certain frequency tunability.
175 citations
TL;DR: The experimental results agree very well with theoretical predictions that the enhancement factor of the spectral sensitivity is equal to the group index n(g) of the slow-light medium.
Abstract: We demonstrate experimentally that the spectral sensitivity of an interferometer can be greatly enhanced by introducing a slow-light medium into it. The experimental results agree very well with theoretical predictions that the enhancement factor of the spectral sensitivity is equal to the group index ng of the slow-light medium.
164 citations
TL;DR: In this paper, a time-dependent analysis of four-wave mixing (FWM) in molecular magnets via electromagnetically induced transparency was performed and the analytical expressions of pulsed electromagnetic waves, including the FWM-generated pulse, group velocities, phase shifts, and absorption coefficients were obtained.
Abstract: We perform a time-dependent analysis of four-wave mixing (FWM) in molecular magnets via electromagnetically induced transparency and obtain the analytical expressions of pulsed electromagnetic waves, including the FWM-generated pulse, group velocities, phase shifts, and absorption coefficients. We have also investigated analytically the time-dependent electromagnetically induced transparency in molecular magnets.
151 citations
TL;DR: This technique allows negative refraction in the optical regime at densities where the magnetic susceptibility is still small and with refraction/absorption ratios that are orders of magnitude larger than those achievable previously.
Abstract: We show that negative refraction with minimal absorption can be obtained by means of quantum interference effects similar to electromagnetically induced transparency (EIT). Coupling a magnetic dipole transition coherently with an electric dipole transition leads to electromagnetically induced chirality, which can provide negative refraction without requiring negative permeability and also suppress absorption. This technique allows negative refraction in the optical regime at densities where the magnetic susceptibility is still small and with refraction/absorption ratios that are orders of magnitude larger than those achievable previously. Furthermore, the refractive index can be fine-tuned, which is essential for practical realization of subdiffraction-limit imaging. As with EIT, electromagnetically induced chirality should be applicable to a wide range of systems.
137 citations
TL;DR: In this article, the authors theoretically study a parallel optical configuration which includes $N$ periodically coupled whispering-gallery-mode resonators and show that the frequency transparency windows are sharp and highly transparent.
Abstract: We theoretically study a parallel optical configuration which includes $N$ periodically coupled whispering-gallery-mode resonators. The model shows an obvious effect which has a direct analogy with the phenomenon of multiple electromagnetically induced transparency in quantum systems. The numerical simulations illuminate that the frequency transparency windows are sharp and highly transparent. We also briefly discuss the experimental feasibility of the current scheme in two practical systems, microrings and microdisks.
106 citations
TL;DR: It is shown that photon nonlinearities in an electromagnetically induced transparency can be at least 1 order of magnitude larger than predicted in all previous approaches.
Abstract: We show that photon nonlinearities in an electromagnetically induced transparency can be at least 1 order of magnitude larger than predicted in all previous approaches. As an application we demonstrate that in this regime they give rise to very strong photon-photon interactions which are strong enough to make an experimental realization of a photonic Mott insulator state feasible in arrays of coupled ultrahigh-Q microcavities.
106 citations
TL;DR: In this article, the carrier-envelope phase (CEP) of few-cycle laser pulses has profound effects on the bound-state atomic coherence even in the weak-field regime where both tunneling and multiphoton ionization hardly take place.
Abstract: It is shown that the carrier-envelope phase (CEP) of few-cycle laser pulses has profound effects on the bound-state atomic coherence even in the weak-field regime where both tunneling and multiphoton ionization hardly take place. The atomic coherence thus produced is shown to be able to be mapped onto the CEP-dependent signal of quantum beats (and other quantum-interference phenomena) and hence might be used to extract information about and ultimately to measure the carrier-envelope phase.
TL;DR: The observation of lambda-configuration electromagnetically induced transparency as well as optical pumping in rubidium-filled kagome-structure hollow-coated-core photonic crystal fiber is reported.
Abstract: We report the observation of lambda-configuration electromagnetically induced transparency as well as optical pumping in rubidium-filled kagome-structure hollow-coated-core photonic crystal fiber. We show that a polydimethylsiloxane coating of the fiber core reduces the linewidth of the transparency below that which could be expected for an uncoated fiber. The measured 6 MHz linewidth was dominated by optical broadening.
TL;DR: To realize the implementation of the CRIT-structure-based gyroscope, issues that ought to be considered are fully discussed here, such as the fabrication possibility, linewidth, shot-noise-limit sensitivity, and integration.
Abstract: The electromagnetically induced transparency- (EIT)-like phenomenon, called coupled-resonator-induced transparency (CRIT), could occur through a classical mean in a coupled resonator structure, due to classical destructive interference. We propose to utilize this property to construct a miniature highly sensitive gyroscope. We analyze the Sagnac effect in the CRIT structure and point out that the Sagnac phase shift contributed by the whole structure is notably enhanced due to its highly dispersive property. An explicit expression of the phase shift is derived and discussed. To realize the implementation of the CRIT-structure-based gyroscope, issues that ought to be considered are fully discussed here, such as the fabrication possibility, linewidth, shot-noise-limit sensitivity, and integration.
TL;DR: In this article, the authors reported the generation of more than 5 dB of vacuum squeezed light at the rubidium D1 line (795 nm) using periodically poled KTiOPO4 (PPKTP) in an optical parametric oscillator.
Abstract: We report on the generation of more than 5 dB of vacuum squeezed light at the rubidium D1 line (795 nm) using periodically poled KTiOPO4 (PPKTP) in an optical parametric oscillator. We demonstrate squeezing at low sideband frequencies, making this source of non-classical light compatible with bandwidth-limited atom optics experiments. When PPKTP is operated as a parametric amplifier, we show a noise reduction of 4 dB stably locked within the 150 kHz–500 kHz frequency range. This matches the bandwidth of electromagnetically induced transparency (EIT) in rubidium hot vapour cells under the condition of large information delay.
TL;DR: Pulse propagation characteristics such as degree of slowdown, absorption, and pulse distortion are investigated with respect to their dependence on the dephasing rates and pulse width.
Abstract: .A numerical investigation of pulse propagation in a quantum dot structure in the regime of electromagnetically induced transparency is reported. The quantum dot is described as a cone on top of a wetting layer and the calculated energy levels and dipole moments are used in an effective three-level model. Pulse propagation characteristics such as degree of slowdown, absorption, and pulse distortion are investigated with respect to their dependence on the dephasing rates and pulse width. It is seen how Rabi oscillations can seriously distort the pulse when the spectral width of the pulse becomes too large compared to the width of the EIT window.
TL;DR: In this article, the authors describe the theory of paired photon generation in a double-energy atomic system using the Heisenberg-Langevin formalism and evaluate the spectral generation rates and intensity correlation function for the output fields.
Abstract: We describe the theory of paired photon generation in a double-$\ensuremath{\Lambda}$ atomic system. Using the Heisenberg-Langevin formalism we evaluate and analyze the spectral generation rates and intensity correlation function for the output fields. Different regimes of parametric down conversion are analyzed. We discuss the influence of the optical depth and Langevin noise fluctuations on the paired photon generation and predict that at the optical depth of 100 or more the contribution of Langevin noise fluctuations is small and therefore Stokes and anti-Stokes photons are generated mostly in pairs. Comparison between the theory and experiments shows good agreement.
TL;DR: In this article, the existence of two-component composite optical Thirring solitons, which are solely supported by cross focusing of two optical beams, was reported. But the existence was not proved.
TL;DR: In this article, a type of scanning fluorescence microscope was proposed to resolve nanometer-size objects in the far field using the spatial sensitivity of the dark state of electromagnetically induced transparency.
Abstract: We suggest a type of scanning fluorescence microscope that is capable of resolving nanometer-size objects in the far field. The key idea is to use the spatial sensitivity of the dark state of electromagnetically induced transparency and localize an atomic excitation to a spot much smaller than the wavelength of light.
TL;DR: It is found, owing to resonant tunneling, that a large XPM can be achieved with vanishing linear and two-photon absorptions.
Abstract: We propose an asymmetric double AlGaAs/GaAs quantum well structure with a common continuum to generate a large cross-phase modulation (XPM). It is found, owing to resonant tunneling, that a large XPM can be achieved with vanishing linear and two-photon absorptions.
TL;DR: In this paper, an ab initio theory suitable for optical strong-field problems was proposed to estimate the photoabsorption cross section and polarizability near the Ne K edge of a laser-dressed neon gas.
Abstract: Electromagnetically induced transparency is predicted for x rays in laser-dressed neon gas. The x-ray photoabsorption cross section and polarizability near the Ne K edge are calculated using an ab initio theory suitable for optical strong-field problems. The laser wavelength is tuned close to the transition between 1s(-1)3s and 1s(-1)3p approximately 800 nm). The minimum laser intensity required to observe electromagnetically induced transparency is of the order of 10(12) W/cm(2). The ab initio results are discussed in terms of an exactly solvable three-level model. This work opens new opportunities for research with ultrafast x-ray sources.
TL;DR: In this article, all-optical detection of Rydberg states in an effusive atomic beam of strontium atoms using electromagnetically induced transparency (EIT) was reported.
Abstract: We report on the all-optical detection of Rydberg states in an effusive atomic beam of strontium atoms using electromagnetically induced transparency (EIT). Using narrow-linewidth CW lasers we obtain an EIT linewidth of 5 MHz. To illustrate the high spectroscopic resolution offered by this method, we have measured isotope shifts of the 5s18d1D2 and 5s19s1S0 Rydberg states. This technique could be applied to high-resolution, non-destructive measurements of ultra-cold Rydberg gases and plasmas.
TL;DR: In this article, the authors used Discovery funding for the Australian Research Council Project No.676DP0557505, which was supported under the Discovery funding scheme for biomedical data analysis.
Abstract: This research was supported under the Discovery funding
scheme of the Australian Research Council Project No.
DP0557505.
TL;DR: The results show that the can effectively trap and delay light by using ultra-small cavities, which can potentially increase the packing density of optical buffers and bit-shifters if applied to coupled-cavity waveguides.
Abstract: We systematically studied the spectral and temporal characteristics of wavelength-sized ultrahigh-Q photonic crystal nanocavities based on width-modulated line defects. By employing accurate measurements, we confirmed that the cavity exhibits an ultra-sharp resonance width (1.23 pm), an ultrahigh-Q (1.28×106), and an ultra-long photon lifetime (1.12 ns). We discussed the correlation between the spectral and temporal measurements for various cavities, and obtained extremely good agreement. In addition, we demonstrated photon trapping for the side-coupling configuration by employing ring-down measurement, which sheds light on another interesting aspect of this phenomenon. Finally, we performed pulse propagation experiments for samples with different waveguide-cavity coupling configurations, and achieved a smallest group velocity of about 4.6 km/s for a novel configuration. These results show that we can effectively trap and delay light by using ultra-small cavities, which can potentially increase the packing density of optical buffers and bit-shifters if applied to coupled-cavity waveguides.
TL;DR: In this paper, the authors proposed a method to generate entangled coherent states between two spatially separated atomic Bose-Einstein condensates via the technique of electromagnetically induced transparency (EIT).
Abstract: We propose a method to generate entangled coherent states between two spatially separated atomic Bose-Einstein condensates (BECs) via the technique of electromagnetically induced transparency (EIT). Two strong coupling laser beams and two entangled probe laser beams are used to cause two distant BECs to be in EIT states and to generate an atom-photon entangled state between probe lasers and distant BECs. The two BECs are initially in unentangled product coherent states while the probe lasers are initially in an entangled state. Entangled states of two distant BECs can be created through the performance of projective measurements upon the two outgoing probe lasers under certain conditions. Concretely, we propose two protocols to show how to generate entangled coherent states of the two distant BECs. One is a single-photon scheme in which an entangled single-photon state is used as the quantum channel to generate entangled distant BECs. The other is a multiphoton scheme where an entangled coherent state of the probe lasers is used as the quantum channel. Additionally, we also obtain some atom-photon entangled states of particular interest such as entangled states between a pair of optical Bell states (or quasi-Bell-states) and a pair of atomic entangled coherent states (or quasi-Bell-states).
TL;DR: The ultraslow propagation of squeezed vacuum pulses with electromagnetically induced transparency is observed with high precision using a homodyne method.
Abstract: We have succeeded in observing ultraslow propagation of squeezed vacuum pulses with electromagnetically induced transparency. Squeezed vacuum pulses (probe lights) were incident on a laser-cooled $^{87}\mathrm{Rb}$ gas together with an intense coherent light (control light). A homodyne method sensitive to the vacuum state was employed for detecting the probe pulse passing through the gas. A delay of $3.1\text{ }\text{ }\ensuremath{\mu}\mathrm{s}$ was observed for the probe pulse having a temporal width of $10\text{ }\text{ }\ensuremath{\mu}\mathrm{s}$.
TL;DR: It is shown that a probe field can acquire a large, frequency tunable, gain- assisted nonlinear phase shift and yet travel with gain-assisted superluminal propagation velocity, raising the possibility of rapidly responding, frequency Tunable non linear phase switching and phase gates for information science.
Abstract: A four-level scheme with a two-mode active Raman gain core is investigated for large and rapidly responding Kerr effect enhancement at room temperature. The new scheme is fundamentally different from the electromagnetically induced transparency (EIT-)based ultraslow-wave Kerr effect enhancement scheme. It eliminates the requirement of group velocity matching and multispecies medium. It also eliminates significant probe field attenuation or distortion associated with weakly driven EIT-based schemes. We show that a probe field can acquire a large, frequency tunable, gain-assisted nonlinear phase shift and yet travel with gain-assisted propagation velocity. This raises the possibility of rapidly responding, frequency tunable nonlinear phase switching and phase gates for information science.
TL;DR: In this article, the effect of double EIT on nonlinear light generation based on the four-wave-mixing (FWM) technique is also investigated, and it is shown that the four wave mixing efficiency can be effectively controlled by varying the strength of the pump field.
Abstract: We have studied nonlinear quantum optical effects in a doubly driven four-level atomic system in a homogeneously broadened regime. On application of two strong fields the system can be made to display double electromagnetically induced transparency (EIT) because of constructive quantum interference giving rise to nonlinear absorption at three-photon resonance condition. This fact may be used to obtain other phenomena like the effect of photon switching in a pulsed regime and large cross phase modulation (XPM) effect. We also show that the behaviour of spatial modulation of transparency of the weak probe beam in a three-level system interacted with a strong standing wave pump field can be dramatically changed in our four-level ladder type system. Here, strong coupling field acting on the uppermost transition is represented by a standing wave whereas strong pump and weak probe fields acting successively on the lower transitions are represented by travelling waves. The effect of double EIT on nonlinear light generation based on the four-wave-mixing (FWM) technique is also investigated. We have examined that the four wave mixing efficiency can be effectively controlled by varying the strength of the pump field.
TL;DR: In this article, the authors show how the slow light propagation through a four-level N-type system can be significantly influenced by the application of the Kerr field under the condition of electromagnetically induced transparency.
Abstract: We show how the slow light propagation through a four-level N-type system can be significantly influenced by the application of the Kerr field under the condition of electromagnetically induced transparency. The change due to the Kerr field under fairly general conditions can be about 10-15 %.
TL;DR: In this paper, the authors demonstrate a protocol that enables frequency conversion and routing of quantum information in an adiabatic and thus robust way, based on electromagnetically induced transparency (EIT).
Abstract: We experimentally demonstrate a communication protocol that enables frequency conversion and routing of quantum information in an adiabatic and thus robust way. The protocol is based on electromagnetically induced transparency (EIT) in systems with multiple excited levels: transfer and/or distribution of optical states between different signal modes is implemented by adiabatically changing the control fields. The proof-of-principle experiment is performed using the hyperfine levels of the rubidium D1 line.
TL;DR: In this article, a hybrid mechanism for coherent transmission of photons in the coupled resonator optical waveguide (CROW) by incorporating the electromagnetically induced transparency (EIT) effect into the controllable band gap structure of the CROW was proposed and studied.
Abstract: In this paper, we propose and study a hybrid mechanism for coherent transmission of photons in the coupled resonator optical waveguide (CROW) by incorporating the electromagnetically induced transparency (EIT) effect into the controllable band gap structure of the CROW. Here, the configuration setup of system consists of a CROW with homogeneous couplings and the artificial atoms with Lambda-type three levels doped in each cavity. The roles of three levels are completely considered based on a mean field approach where the collection of three-level atoms collectively behave as two-mode spin waves. We show that the dynamics of low excitations of atomic ensemble can be effectively described by a coupling boson model. The exact solutions show that the light pulses can be stopped and stored coherently by adiabatically controlling the classical field.