The spectral and temporal response of an optical cavity resonantly coupled to ensemble barium atoms has been investigated experimentally. empty-cavity trnasmission resonances are found split in the presence and, under these conditions, cavity's is be oscillatory. These effects may viewed as a manifestation vacuum-field Rabi splitting, or simple consequence linear absorption dispersion intracavity atoms.

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 greatly enhance nonlinear at low light intensities. The measured is comparable magnitude to dispersion a simple two-level system several orders greater than conventional three-level scheme under similar conditions.

We analyze a four-wave-mixing (FWM) scheme in five-level atomic system based on electromagnetically induced transparency (EIT). show that EIT suppresses both two-photon and three-photon absorptions the FWM enables four-wave mixing to proceed through real, resonant intermediate states without absorption loss. The results several orders of magnitude increase efficiency comparison with recent [Phys. Rev. Lett. 88, 143902 (2002)] may be used for generating short-wavelength radiation at low pump...

We report an experimental demonstration of photon switching by quantum interference in a four-level atomic system proposed Harris and Yamamoto [Phys. Rev. Lett. 81, 3611 (1998)]. Quantum inhibits single-photon absorption but enhances third-order, two-photon-type the system. have observed greatly enhanced nonlinear realized with cold ${}^{87}\mathrm{Rb}$ atoms demonstrated fast pulsed pump laser.

We propose and analyze a hyper-Raman scheme for generation of coherent light in five-level atomic system based on electromagnetically induced transparency (EIT). show that EIT suppresses linear nonlinear photon absorption enables the process to proceed through real, near-resonant intermediate states. The greatly enhances efficiency may be used generating short-wavelength radiation at low pump intensities.

We report an experimental study of resonant six-wave mixing in coherently prepared Rb atoms. Electromagnetically induced transparency a four-level atomic system suppresses the linear susceptibility and enhances nonlinear susceptibilities, which leads to resonantly enhanced, slow-photon at low light intensities. The emission process can be viewed as resulting from diffraction slow off grating by standing-wave pump field.

It is shown that a closed V-type, three-level system, which incoherently pumped on the transition at lasing occurs and coherently other transition, exhibits without population inversion in any atomic state basis. The same system can be also made to exhibit bare basis but with dressed-state

We report experimental observations of interference between three-photon and one-photon excitations, phase control light attenuation and/or transmission in a four-level system. Either constructive or destructive interferences can be obtained by varying the frequency weak laser. The enables absorptive switching one field another at different frequencies ultralow levels.

We report experimental measurements of the transmission spectrum an optical cavity coupled with cold Rb atoms. observe multiatom vacuum Rabi splitting a composite and atom system. When coupling field is applied to atoms induces resonant two-photon Raman transition in $\ensuremath{\Lambda}$-type system, we two sidebands central peak representing intracavity dark state. The linewidth significantly narrowed by dark-state resonance its position insensitive frequency change empty cavity.

Dicke state, a coherent state of multiple particles, is fundamentally responsible for various intriguing collective behaviors many-body systems. Experimental access to states with scalable and deterministic number particles essential study how properties depend on the particle number. We report observation consisting two, three, four, five, six, seven atoms in an atomic vapor. Quantum coherences between ground multi-atom are created detected by using optical two-dimensional spectroscopy. The...

We have measured the emission spectrum of two-level-like Ba atoms driven by two strong, equal-amplitude fields with frequency separation 2\ensuremath{\delta}. The consists a series peaks an essentially constant spacing \ensuremath{\delta} and alternating linewidths. These features differ qualitatively from characteristic triplet observed in case strong monochromatic excitation. Certain such as its comblike structure can be motivated terms energy atom--bichromatic-field product states. Other...

We develop a theoretical framework for calculating the spectrum of resonance fluorescence emitted by two-level atoms that are excited strong bichromatic field. The dressed states system is interacting with fully modulated field identified, and spectral features interpreted in terms transitions among these states.

We propose and analyze theoretically a scheme for atomic guiding cooling in dark hollow laser beam generated from the collimated output of ${\mathrm{LP}}_{01}$ mode micrometer-sized optical fiber. In scheme, cold atoms magneto-optical trap are loaded into blue-detuned beam, move down experience transverse Sisyphus induced by weak repumping beam. longitudinal direction, guided heating gravity field upward-propagating estimate two-dimensional equilibrium temperature, final mean velocity, total...

Quantum fluctuations of an optical transition moment are observed to be suppressed by strong coherent excitation a weak auxiliary transition. The stabilization is manifest through the appearance subnatural linewidths in resonance fluorescence spectrum and due mixing atomic states. Our results quantitative agreement with predictions L. M. Narducci et al. [Phys. Rev. A 42, 1630 (1990)].

The radiative emission of strongly driven, two-level-like barium atoms into the modes a confocal optical cavity is studied as function density. As density increased, spatial profile, intensity, and spectrum light emitted out ends display dramatic changes indicative transition from fluorescence to lasing. In this novel two-level system, laser action can be explained in terms an inversion between dressed atom-field states or type stimulated hyper-Raman scattering which lase ground excited...

Optical double-quantum two-dimensional coherent spectroscopy (2DCS) was implemented to probe interatomic dipole-dipole interactions in both potassium and rubidium atomic vapors. The interaction detected at densities of $4.81 \times 10^8$ cm$^{-3}$ $8.40 10^9$ for rubidium, respectively, corresponding a mean separation 15.8 $\mu$m or $3.0\times 10^5a_0$ 6.1 $1.2\times where $a_0$ is the Bohr radius. We report lowest density which are detected. experimental results confirm long range nature...

We report an experimental observation of doubly dressed states in ${}^{87}\mathrm{Rb}$ atoms cooled and confined a magneto-optical trap. The are produced by strong-coupling laser moderate pump three-level atomic configuration. absorption spectrum weak probe reveals three-peaked spectral profile that can be interpreted dressed-state picture agrees well with calculations based on the density-matrix equations.

In a three-level atomic system coupled by two equal-amplitude laser fields with frequency separation 2\ensuremath{\delta}, weak probe field exhibits multiple-peaked absorption spectrum constant peak \ensuremath{\delta}. The corresponding dispersion steep normal near the minimum between multiple peaks, which leads to simultaneous slow group velocities for photons at frequencies separated We report an experimental study in such bichromatically \ensuremath{\Lambda} cold ${}^{87}\mathrm{Rb}$...

Electromagnetically induced transparency may lead to suppression of two-photon absorption in a four-level atomic system. This phenomenon is manifested by destructive quantum interference among multiple excitation paths created coherent coupling field. We report an experimental observation such cold ${}^{87}\mathrm{Rb}$ atoms.

Electromagnetically induced transparency in a four-level atomic system suppresses the linear susceptibility and enhances nonlinear susceptibilities, which leads to resonantly enhanced slow-light four-wave mixing at low light intensities. We report an experimental observation of such resonant cold Rb atoms.

We analyze the optical potential for atom guidance in a dark hollow laser beam and compare it with that generated by evanescent wave micrometer-sized fiber. calculate dependence of on various parameters: radial position r, laser–atom detuning Δ, power P0, propagation distance Z. experimentally from fiber 7-μm hole diameter obtained coupling efficiency ∼50% LP01 mode. Our study shows can produce an deep enough to guide cold atoms magneto-optical trap.

We analyze transient properties of light amplification in a coherently coupled three-level \ensuremath{\Lambda}-type system and study the evolution from regime into steady state. From time atomic coherence population distribution, we discuss mechanism with without inversion. also solve density-matrix equations state derive conditions for existence specific mechanisms, such as inversion any standard basis, by stimulated Raman scattering, dressed states.

We report an experimental observation of slow light propagation in cold Rb atoms exhibiting cavity electromagnetically induced transparency (EIT). The steep slope the atomic dispersion manifested by EIT reduces group velocity. filtering and feedback further contribute to slowdown delay pulse propagation. A combination system significantly improves performance time approximately 200 ns was observed system, which is 70 times greater than calculated for through same without cavity.

We report an experimental demonstration of all-optical switching at ultralow light levels in coherently prepared Rb atoms. A signal pulse is switched on and off by a control different frequencies four-level atomic system based multiphoton interferences. observed efficiency 55% with the pulses containing approximately 20 photons each, corresponding to energy density 10(-5) per cross section lambda(2)/(2pi).