We propose an optical cavity-QED scheme for the deterministic generation of polarization-entangled photon pairs that operates with high fidelity even in the bad cavity limit. The scheme is based on the interaction of an excited four-level atom with two empty optical cavity modes via an adiabatic passage process. Monte Carlo wavefunction simulations are used to evaluate the fidelity of the cavity-QED source and its entanglement capability in the presence of decoherence. In the bad cavity limit, fidelities close to one are predicted for state-of-the-art experimental parameter values.

}, url = {http://stacks.iop.org/0953-4075/41/i=4/a=045505}, author = {R. Garc{\'\i}a-Maraver and K. Eckert and R. Corbal{\'a}n and J. Mompart} } @article {1742-6596-84-1-012008, title = {Cavity-QED-based entangled photon pair gun}, journal = {Journal of Physics: Conference Series}, volume = {84}, number = {1}, year = {2007}, pages = {012008}, abstract = {We describe a cavity-QED scheme to deterministically generate polarization entangled photon pairs by using a single atom successively coupled to two single longitudinal mode cavities presenting polarization degeneracy. The cavities are initially prepared either in the vacuum state or in a single photon Fock state for each orthogonal polarization. Sharing the same basic elements, the source can operate on different physical processes. For a V -type three-level atom initially prepared in the ground state two implementations of the source are possible using either: i) two truncated Rabi Oscillations, or ii) a counterintuitive Stimulated Raman Adiabatic Passage process. Although slower than the former implementation, this second one is very efficient and robust under fluctuations of the experimental parameters and, particularly interesting, almost insensitive to atomic decay. For a four-level atom in a diamond configuration initially prepared in the upper state, the source can produce entangled photon pairs even in the bad cavity limit via an adiabatic passage process. We have performed Monte Carlo wave function simulations to characterize these sources by means of: i) the success probability P of producing the desired entangled state, ii) the fidelity F in the reduced space of two emitted cavity photons, and iii) the S parameter of the Clauser-Horne-Shimony-Holt (CHSH) inequality to quantify the entanglement capability.

}, url = {http://stacks.iop.org/1742-6596/84/i=1/a=012008}, author = {R. Garc{\'\i}a-Maraver and K. Eckert and R. Corbal{\'a}n and J. Mompart} } @article {Garcia-Maraver:07, title = {Cavity-quantum-electrodynamics entangled photon source based on two truncated Rabi oscillations}, journal = {J. Opt. Soc. Am. B}, volume = {24}, number = {2}, year = {2007}, month = {Feb}, pages = {257{\textendash}265}, publisher = {OSA}, abstract = {We discuss a cavity-QED scheme to deterministically generate entangled photons pairs by using a three-level atom successively coupled to two single longitudinal mode high-Q cavities presenting polarization degeneracy. The first cavity is prepared in a well-defined Fock state with two photons with opposite circular polarizations while the second cavity remains in the vacuum state. Half of a resonant Rabi oscillation in each cavity transfers one photon from the first to the second cavity, leaving the photons entangled in their polarization degree of freedom. The feasibility of this implementation and some practical considerations are discussed for both microwave and optical regimes. In particular, Monte Carlo wave-function simulations have been performed with state-of-the-art parameter values to evaluate the success probability of the cavity-QED source in producing entangled photon pairs as well as its entanglement capability.

}, keywords = {Photon statistics, Quantum electrodynamics}, doi = {10.1364/JOSAB.24.000257}, url = {http://josab.osa.org/abstract.cfm?URI=josab-24-2-257}, author = {R. Garc{\'\i}a-Maraver and K. Eckert and R. Corbal{\'a}n and J. Mompart} } @article {1367-2630-9-1-004, title = {Quantum switches and quantum memories for matter-wave lattice solitons}, journal = {New Journal of Physics}, volume = {9}, number = {1}, year = {2007}, pages = {4}, abstract = {We study the possibility of implementing a quantum switch and a quantum memory using matter-wave lattice solitons and making them interact with {\textquoteright}effective{\textquoteright} potentials (barrier/well) corresponding to defects of the optical lattice. In the case of interaction with an {\textquoteright}effective{\textquoteright} potential barrier, the bright lattice soliton experiences an abrupt transition from complete transmission to complete reflection (quantum switch) for a critical height of the barrier. The trapping of the soliton in an {\textquoteright}effective{\textquoteright} potential well and its release on demand, without losses, shows the feasibility of using the system as a quantum memory. The inclusion of defects as a way of controlling the interactions between two solitons is also reported.}, url = {http://stacks.iop.org/1367-2630/9/i=1/a=004}, author = {V. Ahufinger and A Mebrahtu and R. Corbal{\'a}n and A. Sanpera} } @article {PhysRevA.75.023801, title = {Ultrashort pulse control of space-dependent excitations in a three-level system}, journal = {Phys. Rev. A}, volume = {75}, year = {2007}, month = {Feb}, pages = {023801}, publisher = {American Physical Society}, abstract = {Coherent control of regions with spatial excitation of populations and coherence between two lower states in three-level Λ-type quantum systems mediated by the self-induced transparency (SIT) phenomenon is theoretically investigated with one- and two-color ultrashort pulses and with pulse sequences beyond the slowly varying envelope (SVEA) and rotating wave (RWA) approximations. The effects of different parameters characterizing the pulses and the medium on the location as well as the width of such excited regions have been studied numerically by means of the finite-difference time-domain (FDTD) method. It has been determined that with a scheme of two-pulse excitation one can effectively control the position at which the region is written and its width. In particular, the position of the excited region can be controlled by the area of the pulses. We find that the maximum value of the population transferred to the lower excited state depends on the detuning of the pulses with respect to the one-photon resonances, and that both position and width of the region also depend on the temporal duration of the pulses. We show how after the excited region is written, its position can be shifted by additional pulses. On the basis of numerical results, scaling laws are formulated for the reported phenomena. With such control, the width of the region excited inside the medium can be reduced to the order of the wavelength of the light.}, doi = {10.1103/PhysRevA.75.023801}, url = {http://link.aps.org/doi/10.1103/PhysRevA.75.023801}, author = {Yu. V. Loiko and C. Serrat and R. Vilaseca and V. Ahufinger and J. Mompart and R. Corbal{\'a}n} } @article {PhysRevA.74.031801, title = {Deterministic cavity-QED source of polarization-entangled photon pairs}, journal = {Phys. Rev. A}, volume = {74}, year = {2006}, month = {Sep}, pages = {031801}, publisher = {American Physical Society}, abstract = {We present two cavity quantum electrodynamics proposals that, sharing the same basic elements, allow for the deterministic generation of entangled photon pairs by means of a three-level atom successively coupled to two single longitudinal mode high-Q optical resonators presenting polarization degeneracy. In the faster proposal, the three-level atom yields a polarization-entangled photon pair via two truncated Rabi oscillations, whereas in the adiabatic proposal, a counterintuitive stimulated Raman adiabatic passage process is considered. Although slower than the former process, this second method is very efficient and robust under fluctuations of the experimental parameters and, particularly interesting, almost completely insensitive to atomic decay.

}, doi = {10.1103/PhysRevA.74.031801}, url = {http://link.aps.org/doi/10.1103/PhysRevA.74.031801}, author = {R. Garc{\'\i}a-Maraver and K. Eckert and R. Corbal{\'a}n and J. Mompart} } @article {Eckert2006264, title = {Three level atom optics in dipole traps and waveguides}, journal = {Optics Communications}, volume = {264}, number = {2}, year = {2006}, note = {Quantum Control of Light and Matter In honor of the 70th birthday of Bruce Shore}, pages = {264 - 270}, abstract = {An analogy is explored between a setup of three atomic traps coupled via tunneling and an internal atomic three-level system interacting with two laser fields. Within this scenario we describe a \{STIRAP\} like process which allows to move an atom between the ground states of two trapping potentials and analyze its robustness. This analogy is extended to other robust and coherent transport schemes and to systems of more than a single atom. Finally it is applied to manipulate external degrees of freedom of atomic wave packets propagating in waveguides.}, issn = {0030-4018}, doi = {http://dx.doi.org/10.1016/j.optcom.2006.02.056}, url = {http://www.sciencedirect.com/science/article/pii/S003040180600486X}, author = {K. Eckert and J. Mompart and R. Corbal{\'a}n and M. Lewenstein and G. Birkl} } @article { ISI:000225524900010, title = {Frequency up-conversion He-Ne laser without inversion}, journal = {Applied Physics B-Lasers and Optics}, volume = {80}, number = {1}, year = {2005}, month = {JAN}, pages = {67-72}, publisher = {{SPRINGER}}, address = {{233 SPRING STREET, NEW YORK, NY 10013 USA}}, abstract = {{A scheme for obtaining up-conversion lasing without inversion in the visible range is proposed using a Doppler-broadened He-Ne mixture as active medium. We consider a cascade scheme (2s(2) <{\textendash}{\textendash}> 2p(2) <{\textendash}{\textendash}> 1s(3)) with a frequency upconversion ratio of 1.91. The upper transition is inverted and driven by an external field and lasing without inversion occurs at 616.4 nm provided that the collisional decay rates of the 1s(3) and 1s(5) levels overcome a certain threshold.}}, issn = {0946-2171}, doi = {10.1007/s00340-004-1694-0}, author = {V. Ahufinger and R Shuker and R. Corbal{\'a}n} } @article {PhysRevA.70.062324, title = {Cavity QED quantum phase gates for a single longitudinal mode of the intracavity field}, journal = {Phys. Rev. A}, volume = {70}, year = {2004}, month = {Dec}, pages = {062324}, publisher = {American Physical Society}, abstract = {A single three-level atom driven by a longitudinal mode of a high-Q cavity is used to implement two-qubit quantum phase gates for the intracavity field. The two qubits are associated with the zero- and one-photon Fock states of each of the two opposite circular polarization states of the field. The three-level atom mediates the conditional phase gate provided the two polarization states and the atom interact in a V-type configuration and the two-photon resonance condition is satisfied. Microwave and optical implementations are discussed with gate fidelities being evaluated against several decoherence mechanisms such as atomic velocity fluctuations or the presence of a weak magnetic field. The use of coherent states for both polarization states is investigated to assess the entanglement capability of the proposed quantum gates.

}, doi = {10.1103/PhysRevA.70.062324}, url = {http://link.aps.org/doi/10.1103/PhysRevA.70.062324}, author = {R. Garc{\'\i}a-Maraver and R. Corbal{\'a}n and K. Eckert and S. Rebic and M. Artoni and J. Mompart} } @booklet {doi:10.1117/12.589360, title = {Single three-level atoms for quantum information}, howpublished = {Proc. SPIE}, volume = {5622}, year = {2004}, pages = {430-434}, abstract = {A single three-level atom in interaction with a single longitudinal mode of a high-Q cavity is used to quantum engineer the intracavity field. In our proposal the quantum bit states correspond to the vacuum and single photon Fock states of each of two circular polarization states of the longitudinal mode. We show that for particular velocities of the three-level atom crossing the cavity it is possible to implement in one single step a two-qubit quantum phase gate between the two circular polarization states. Fidelity against several decoherence mechanisms such as atomc velocity fluctuations or the presence of a weak magnetic field along the cavity axis is analyzed.

}, doi = {10.1117/12.589360}, url = {http://dx.doi.org/10.1117/12.589360}, author = {J. Mompart and R. Garc{\'\i}a-Maraver and R. Corbal{\'a}n} } @article {PhysRevA.70.023606, title = {Three-level atom optics via the tunneling interaction}, journal = {Phys. Rev. A}, volume = {70}, year = {2004}, month = {Aug}, pages = {023606}, publisher = {American Physical Society}, abstract = {Three-level atom optics is introduced as a simple, efficient, and robust method to coherently manipulate and transport neutral atoms. The tunneling interaction among three trapped states allows us to realize the spatial analog of the stimulated Raman adiabatic passage, coherent population trapping, and electromagnetically induced transparency techniques and offers a wide range of possible applications. We investigate an implementation in optical microtrap arrays and show that under realistic parameters the coherent manipulation and transfer of neutral atoms among dipole traps could be realized in the millisecond range.}, doi = {10.1103/PhysRevA.70.023606}, url = {http://link.aps.org/doi/10.1103/PhysRevA.70.023606}, author = {K. Eckert and M. Lewenstein and R. Corbal{\'a}n and G. Birkl and W. Ertmer and J. Mompart} } @article {PhysRevLett.91.083901, title = {Cavity Solitons in Two-Level Lasers with Dense Amplifying Medium}, journal = {Phys. Rev. Lett.}, volume = {91}, year = {2003}, month = {Aug}, pages = {083901}, publisher = {American Physical Society}, abstract = {Local-field effects are known to induce bistability in dense optical media. We examine theoretically whether this property is preserved in broad-area cavities, and show that bistability between the homogeneous lasing and nonlasing states of the system persists provided a Fourier filtering technique is used to prevent off-axis emission. The resulting bistability gives rise to spatial light localization in the form of cavity solitons, which exhibit a particularly large degree of plasticity as a function of the characteristics of the addressing beam. This is the simplest laser able to sustain cavity solitons.}, doi = {10.1103/PhysRevLett.91.083901}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.91.083901}, author = {V. Ahufinger and J. Garc{\'\i}a-Ojalvo and J. Mompart and M. C. Torrent and R. Corbal{\'a}n and R. Vilaseca} } @article {1464-4266-5-3-301, title = {Enlargement of the inversionless lasing domain by using broad-area cavities}, journal = {Journal of Optics B: Quantum and Semiclassical Optics}, volume = {5}, number = {3}, year = {2003}, pages = {201}, abstract = {We investigate analytically and numerically the role of diffraction in the operation of a broad-area inversionless laser in a cascade three-level configuration. Through a linear stability analysis of the trivial non-lasing solution and numerical integration of the corresponding Maxwell{\textendash}Schr{\"o}dinger equations, we show that off-axis emission allows stationary inversionless lasing over a cavity detuning range much larger than in small-aspect-ratio cavities and in conventionally inverted three-level lasers. In addition, we investigate inversionless lasing in a self-pulsing regime in the presence of diffraction, which leads to rich spatiotemporal dynamics.}, url = {http://stacks.iop.org/1464-4266/5/i=3/a=301}, author = {J. Mompart and M. C. Torrent and V. Ahufinger and J. Garc{\'\i}a-Ojalvo and R. Corbal{\'a}n and R. Vilaseca} } @article {1464-4266-5-3-311, title = {Gain without inversion at two symmetrical sidebands of resonance in cold free 87 Rb atoms: an experimental proposal}, journal = {Journal of Optics B: Quantum and Semiclassical Optics}, volume = {5}, number = {3}, year = {2003}, pages = {268}, abstract = {We propose an experiment for obtaining about 0.4\% inversionless gain at the sidebands of resonance in cold free 87 Rb atoms. This gain is of the same order of magnitude as the one already observed near resonance (Kitching and Hollberg 1999 Phys. Rev. A 59 4685).}, url = {http://stacks.iop.org/1464-4266/5/i=3/a=311}, author = {V. Ahufinger and R. Corbal{\'a}n} } @article {Mompart:03, title = {Quantum-jump statistical analysis of three-level systems with arbitrary coupling laser intensities and detunings}, journal = {J. Opt. Soc. Am. B}, volume = {20}, number = {11}, year = {2003}, month = {Nov}, pages = {2368{\textendash}2376}, publisher = {OSA}, abstract = {We develop the quantum-jump statistical tools required to analyze the probe response in three-level systems where the probe and driving lasers have arbitrary intensities and detunings. We apply these tools to investigate the appearance of two inversionless amplification sidebands in the probe spectrum as the driving laser intensity increases.}, keywords = {Coherent optical effects, Laser theory, Multiphoton processes}, doi = {10.1364/JOSAB.20.002368}, url = {http://josab.osa.org/abstract.cfm?URI=josab-20-11-2368}, author = {J. Mompart and R. Corbal{\'a}n} } @article {Ahufinger2002159, title = {Electromagnetically induced transparency in a Bose{\textendash}Einstein condensate}, journal = {Optics Communications}, volume = {211}, number = {1{\textendash}6}, year = {2002}, pages = {159 - 165}, abstract = {We report on the direct observation of the electromagnetically induced transparency (EIT) lineshape of cold 87Rb atoms above and below the transition temperature for Bose{\textendash}Einstein condensation (BEC). Similar results are observed in both temperature regimes, with an absorption reduction of about 60\%. Good agreement with a theoretical model is discussed.}, issn = {0030-4018}, doi = {http://dx.doi.org/10.1016/S0030-4018(02)01826-6}, url = {http://www.sciencedirect.com/science/article/pii/S0030401802018266}, author = {V. Ahufinger and R. Corbal{\'a}n and F. Cataliotti and S. Burger and F. Minardi and C. Fort} } @article {PhysRevLett.88.023603, title = {Coherent Population Trapping in Two-Electron Three-Level Systems with Aligned Spins}, journal = {Phys. Rev. Lett.}, volume = {88}, year = {2001}, month = {Dec}, pages = {023603}, publisher = {American Physical Society}, abstract = {The possibility of coherent population trapping in two electron states with aligned spins (orthosystem) is evidenced. From the analysis of a three-level atomic system containing two electrons, and driven by the two laser fields needed for coherent population trapping, a conceptually new kind of dark state appears. The properties of this trapping are physically interpreted in terms of a dark hole, instead of a dark two-electron state. This technique, among many other applications, offers the possibility of measuring, with subnatural resolution, some superposition-state matrix elements of the electron-electron correlation that due to their time dependent nature are inaccessible by standard measuring procedures.}, doi = {10.1103/PhysRevLett.88.023603}, url = {http://link.aps.org/doi/10.1103/PhysRevLett.88.023603}, author = {J. Mompart and R. Corbal{\'a}n and L. Roso} } @article {PhysRevA.64.033802, title = {Electromagnetically induced transparency with a standing-wave drive in the frequency up-conversion regime}, journal = {Phys. Rev. A}, volume = {64}, year = {2001}, month = {Aug}, pages = {033802}, publisher = {American Physical Society}, abstract = {We study electromagnetically induced transparency for a probe traveling-wave (TW) laser field in closed Doppler-broadened three-level systems driven by a standing-wave (SW) laser field of moderate intensity (its Rabi frequencies are smaller than the Doppler width of the driven transition). We show that probe windows of transparency occur for values of the probe to drive field frequency ratio R close to half-integer values. For optical transitions and typical values of Doppler broadening for atoms in a vapor cell, we show that for R>1 a SW drive field is appreciably more efficient than a TW drive in inducing probe transparency. As examples, we consider parameters for real cascade schemes in barium atoms with R≈1.5 and in beryllium atoms with R≈3.5 showing that probe transmission values well above 50\% are possible for conditions in which it is almost negligible either without driving field or with only one of the TW components of the drive. We show that a strongly asymmetric drive having two TW components with unequal intensities is even more eficient than a symmetric SW drive in inducing probe transparency. The case of arbitrary probe intensity is also considered.}, doi = {10.1103/PhysRevA.64.033802}, url = {http://link.aps.org/doi/10.1103/PhysRevA.64.033802}, author = {F. Silva and J. Mompart and V. Ahufinger and R. Corbal{\'a}n} } @article {PhysRevA.63.063810, title = {Generalized Einstein B coefficients for coherently driven three-level systems}, journal = {Phys. Rev. A}, volume = {63}, year = {2001}, month = {May}, pages = {063810}, publisher = {American Physical Society}, abstract = {Generalized Einstein B coefficients for coherently driven closed three-level systems are introduced by means of the quantum-jump technique. The nonreciprocity between stimulated emission and absorption for both one-photon and two-photon gain and loss processes has been studied and quantified in terms of the rates of the particular incoherent processes present in each three-level system. Some general properties of these generalized Einstein B coefficients have been found. In particular, whenever the generalized Einstein B coefficient for one-photon gain overcomes that for one-photon loss then the generalized Einstein B coefficient for two-photon loss overcomes that for two-photon gain, and vice versa. Finally, we have obtained simple analytical expressions indicating the way to maximize the asymmetry between stimulated emission and absorption coefficients either for one-photon or for two-photon processes.}, doi = {10.1103/PhysRevA.63.063810}, url = {http://link.aps.org/doi/10.1103/PhysRevA.63.063810}, author = {J. Mompart and R. Corbal{\'a}n} } @article {0295-5075-51-3-286, title = {Electromagnetically induced transparency in Doppler-broadened three-level systems with resonant standing-wave drive}, journal = {EPL (Europhysics Letters)}, volume = {51}, number = {3}, year = {2000}, pages = {286}, abstract = {We study electromagnetically induced transparency for a probe travelling-wave (TW) laser field in closed Doppler-broadened three-level systems driven by a resonant standing-wave (SW) laser field of moderate intensity (its Rabi frequencies are smaller than the Doppler width of the driven transition). We show that probe windows of transparency occur only for values of the probe-to-drive field frequency ratio R close to half-integer values. For optical transitions and typical values of Doppler broadening for atoms in a vapor cell, we show that for R > 1 a SW drive field is appreciably more efficient than a TW driving in inducing probe transparency. As an example, we consider parameters for a real closed cascade scheme in barium atoms with R $\#$$\#$IMG$\#$$\#$ [http://ej.iop.org/icons/Entities/simeq.gif] {simeq} 1.5 showing that probe transmission values of 50\% are possible for cases in which the transmission is almost negligible either without driving field or with only one of the TW components of the drive.}, url = {http://stacks.iop.org/0295-5075/51/i=3/a=286}, author = {F. Silva and J. Mompart and V. Ahufinger and R. Corbal{\'a}n} } @article {1464-4266-2-3-201, title = {Lasing without inversion}, journal = {Journal of Optics B: Quantum and Semiclassical Optics}, volume = {2}, number = {3}, year = {2000}, pages = {R7}, abstract = {This review paper is devoted to amplification and lasing without population inversion involving atomic transitions in gas media. We start by discussing the main motivation in inversionless lasing research, namely, the generation of short-wavelength laser light. Then, we review the basic physics of inversionless lasing in two-level and, eventually, in three- and multilevel atomic configurations. Finally, we summarize the current state of the art of LWI experiments and indicate the main difficulties with respect to short-wavelength laser generation.}, url = {http://stacks.iop.org/1464-4266/2/i=3/a=201}, author = {J. Mompart and R. Corbal{\'a}n} } @article {PhysRevA.61.053814, title = {Lasing without inversion in three-level systems without external coherent driving}, journal = {Phys. Rev. A}, volume = {61}, year = {2000}, month = {Apr}, pages = {053814}, publisher = {American Physical Society}, abstract = {We have studied an incoherently pumped laser operating with a Doppler-broadened three-level system placed in a doubly resonant cavity. This system generates two laser fields, one of them without population inversion. Both ladder and V-type three-level schemes are considered with a ratio R=ωα/ωβ of inversionless laser frequency ωα to ordinary laser frequency ωβ of R=0.67 and R=1.88, respectively. Dual-wavelength lasing extends up to Doppler-broadening values for optical transitions of atoms in a vapor cell. Some considerations for the practical realization of this dual-wavelength laser are discussed.}, doi = {10.1103/PhysRevA.61.053814}, url = {http://link.aps.org/doi/10.1103/PhysRevA.61.053814}, author = {V. Ahufinger and J. Mompart and R. Corbal{\'a}n} } @article {1464-4266-2-3-321, title = {Propagation effects on lasing without population inversion}, journal = {Journal of Optics B: Quantum and Semiclassical Optics}, volume = {2}, number = {3}, year = {2000}, pages = {359}, abstract = {We study propagation effects on lasing without population inversion in a Doppler-broadened V -type three-level system. In particular, we focus our analysis on frequency up-conversion lasing without inversion in atomic rubidium. In an atomic beam configuration, we show that it is possible to increase notably the probe gain per single pass through the active medium by detuning driving and probe fields out of one-photon resonance but maintaining the two-photon resonance condition. In a vapour cell configuration, we show that due to propagation effects the probe gain per single pass depends strongly on the driving field intensity at the entrance of the active medium. In fact, for appropriate parameter values, it is possible to reach values of the probe gain per single pass of around 40\%. For this last case, we have considered the feedback of a ring laser cavity.}, url = {http://stacks.iop.org/1464-4266/2/i=3/a=321}, author = {J. Mompart and V. Ahufinger and R. Corbal{\'a}n and F Prati} } @article {PhysRevA.59.3038, title = {Giant pulse lasing in three-level systems}, journal = {Phys. Rev. A}, volume = {59}, year = {1999}, month = {Apr}, pages = {3038{\textendash}3043}, publisher = {American Physical Society}, 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.}, doi = {10.1103/PhysRevA.59.3038}, url = {http://link.aps.org/doi/10.1103/PhysRevA.59.3038}, author = {J. Mompart and R. Corbal{\'a}n and R. Vilaseca} } @article { ISI:000082230000013, title = {Inversionless amplification with standing-wave drive}, journal = {Laser Physics}, volume = {9}, number = {4}, year = {1999}, month = {JUL-AUG}, pages = {858-865}, publisher = {{INTERPERIODICA}}, address = {{PO BOX 1831, BIRMINGHAM, AL 35201-1831 USA}}, abstract = {We study amplification without inversion in closed Doppler-broadened three-level systems driven by a standing-wave (SW) laser field. Our results are compared to those of the well-known case of a traveling-wave drive. A distinguishing feature of the SW case is the contribution to probe the gain of multiphoton processes involving one probe photon and several pump photons, with alternating absorption and emission from the two counterpropagating pump components. These processes are only weakly affected by Doppler broadening for probe to drive frequency ratios R equal to integer numbers. Examples of inversionless amplification with frequency up-conversion ratios R = 3 and R = 4 are presented.}, issn = {1054-660X}, author = {F. Silva and V. Ahufinger and J. Mompart and R. Corbal{\'a}n} } @booklet {doi:10.1117/12.358396, title = {Lasing without inversion: realities and prospects}, howpublished = {Proc. SPIE}, volume = {3572}, year = {1999}, pages = {33-44}, abstract = {We review amplification and lasing without inversion (AWI and LWI) in homogeneously broadened closed three-level systems in the framework of both density-matrix and quantum- jump formalisms. With the density-matrix formalism: (1) we study the nature of quantum interference in these systems; (2) determine analytically the conditions for AWI and locate the position of maxima and minima in the probe absorption spectrum; and (3) study various regimes of lasing, namely, continuous wave, self-pulsing and giant pulse lasing. Within the quantum-jump formalism we calculate the relative probabilities of the various physical processes responsible for probe field amplification and absorption.}, doi = {10.1117/12.358396}, url = {http://dx.doi.org/10.1117/12.358396}, author = {J. Mompart and R. Corbal{\'a}n} } @article {PhysRevA.60.614, title = {Lasing without inversion with frequency up-conversion in a Doppler-broadened V-type three-level system}, journal = {Phys. Rev. A}, volume = {60}, year = {1999}, month = {Jul}, pages = {614{\textendash}620}, publisher = {American Physical Society}, abstract = {We study lasing without inversion in a Doppler-broadened V-type three-level system in the frequency up-conversion regime. We show that the ratio R=ωl/ωd of generated laser frequency to driving laser frequency that can be achieved using a vapor cell is modest (R<~2). Our analysis demonstrates that using an atomic beam the frequency of the generated field can be substantially larger than that of the driving field R\~{}10. Two different configurations are considered: (a) copropagating driving and laser beams orthogonal to the atomic beam, and (b) counterpropagating driving and atomic beams and laser beam at a determined angle with the driving beam.}, doi = {10.1103/PhysRevA.60.614}, url = {http://link.aps.org/doi/10.1103/PhysRevA.60.614}, author = {V. Ahufinger and J. Mompart and R. Corbal{\'a}n} } @article { ISI:000082230000012, title = {Quantum interference and quantum-Zeno effect in amplification without inversion}, journal = {Laser Physics}, volume = {9}, number = {9}, year = {1999}, month = {JUL-AUG}, pages = {844-857}, publisher = {{INTERPERIODICA}}, address = {{PO BOX 1831, BIRMINGHAM, AL 35201-1831 USA}}, abstract = {We analyze amplification without inversion (AWI) in different homogeneously broadened closed three-level systems in the framework of both density-matrix and quantum-jump formalisms. With the density-matrix formalism we study the nature of quantum interference in these systems; determine analytically the condition for AWI and locate the position of maxima and minima in the probe absorption spectrum. Within the quantum-jump formalism we calculate the relative probabilities of the various physical processes responsible for probe field amplification and absorption, and analyze the role of the quantum-Zeno effect in AWI. The result is that AWI in the h and p schemes is due to one-photon processes while for V and Lambda schemes are due to two-photon processes. We also show that AWI in V and h schemes always occurs in the quantum-Zeno regime, while this regime is not necessary for AWI in the Lambda and p schemes.}, issn = {1054-660X}, author = {J. Mompart and V. Ahufinger and F. Silva and R. Corbal{\'a}n and R. Vilaseca} } @article {198, title = {Quantum-jump approach to dipole dephasing: Application to inversionless amplification}, journal = {The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics}, volume = {5}, number = {3}, year = {1999}, pages = {351-356}, publisher = {EDP Sciences, Springer-Verlag}, abstract = {We present a model for simulating atomic dipole dephasing within the Monte-Carlo wave function formalism which leads to the same results as the standard density-matrix formalism. In this model dipole dephasing processes are accounted by quantum-jumps into one of the atomic energy eigenstates. This fact allows us to obtain analytical expressions for the effects of elastic collisions on the various physical processes responsible for amplification without population inversion in a cascade three-level atomic configuration.}, keywords = {Monte-Carlo and statistical methods, Photon interactions with atoms, Quantum optics}, issn = {1434-6060}, doi = {10.1007/PL00021600}, url = {http://dx.doi.org/10.1007/PL00021600}, author = {J. Mompart and R. Corbal{\'a}n} } @article {1464-4266-1-1-026, title = {Transverse profile effects on lasing without population inversion}, journal = {Journal of Optics B: Quantum and Semiclassical Optics}, volume = {1}, number = {1}, year = {1999}, pages = {146}, abstract = {We analyse the effects of a Gaussian transverse profile for the driving and laser fields on lasing without population inversion, in four different three-level schemes. We show that the lasing domains can be considerably reduced with respect to the plane-wave case in the V and in the cascade configuration driven in the upper transition, while in the $\#$$\#$IMG$\#$$\#$ [http://ej.iop.org/icons/common/Lambda.gif] {Lambda} and in the cascade configuration driven in the lower transition such domains are always larger in the Gaussian case.}, url = {http://stacks.iop.org/1464-4266/1/i=1/a=026}, author = {F Prati and J. Mompart and R. Corbal{\'a}n} } @article {1355-5111-10-2-009, title = {Interpretation of transient V scheme amplification without inversion}, journal = {Quantum and Semiclassical Optics: Journal of the European Optical Society Part B}, volume = {10}, number = {2}, year = {1998}, pages = {355}, abstract = {Amplification without inversion (AWI) in a resonant V-type system is studied using a dressed basis which reduces the coherent interaction of both involved optical transitions to that of a single two-level system. The transient AWI recently reported through a numerical analysis of the density matrix equations of the V-system in the bare atom basis (Zhu Y 1996 Phys. Rev . A 53 2742) is damped Rabi nutation with transient population inversion in this dressed basis. Although the transient AWI in the bare state basis occurs both with and without an incoherent pump field, the integrated probe gain is positive only in the first case.}, url = {http://stacks.iop.org/1355-5111/10/i=2/a=009}, author = {J. Mompart and C. Peters and R. Corbal{\'a}n} } @article {Mompart1998133, title = {Inversionless amplification in three-level systems: dressed states quantum interference and quantum-jump analyses}, journal = {Optics Communications}, volume = {156}, number = {1{\textendash}3}, year = {1998}, pages = {133 - 144}, abstract = {We investigate amplification without inversion (AWI) in different three-level systems driven by an on-resonance coherent field and identify the elements that contribute to destructive or constructive dressed states quantum interference in the probe field absorption spectrum. We determine analytically the conditions for \{AWI\} at the probe field line center and at the wings of the resonance region. For this latter case, we explicitly locate the position of the maximum gain as a function of the probe field detuning. Finally, through a quantum-jump analysis, we find that \{AWI\} at the wings of the resonance region is due to an asymmetry between one-photon-stimulated emission and absorption processes, in contrast with \{AWI\} at the line center which arises from the contribution of two-photon gain.}, keywords = {Quantum jumps}, issn = {0030-4018}, doi = {http://dx.doi.org/10.1016/S0030-4018(98)00433-7}, url = {http://www.sciencedirect.com/science/article/pii/S0030401898004337}, author = {J. Mompart and R. Corbal{\'a}n} } @article {Mompart1998299, title = {Lasing without inversion in the V-type three-level system under the two-photon resonance condition}, journal = {Optics Communications}, volume = {147}, number = {4{\textendash}6}, year = {1998}, pages = {299 - 304}, abstract = {We investigate lasing without inversion in the closed V-type three-level system with off-resonant driving and laser fields by using both density-matrix and quantum-jump approaches. We demonstrate analytically and numerically that, under the two-photon resonance condition, it is possible to relax the severe conditions between spontaneous population decay and incoherent pump rates needed in the resonant case. We extend the same analysis to the remaining three-level systems.}, keywords = {atomic coherence}, issn = {0030-4018}, doi = {http://dx.doi.org/10.1016/S0030-4018(97)00490-2}, url = {http://www.sciencedirect.com/science/article/pii/S0030401897004902}, author = {J. Mompart and R. Corbal{\'a}n and R. Vilaseca} } @article {PhysRevA.57.2163, title = {Lasing without inversion in three-level systems: Self-pulsing in the cascade schemes}, journal = {Phys. Rev. A}, volume = {57}, year = {1998}, month = {Mar}, pages = {2163{\textendash}2168}, publisher = {American Physical Society}, abstract = {Lasing without inversion (LWI) in specific models of closed three-level systems is analyzed in terms of nonlinear dynamics. From a linear stability analysis of the trivial nonlasing solution of the homogeneously broadened systems with on-resonance driving and laser fields, we find that, near lasing threshold, resonant closed Λ and V schemes yield continuous-wave LWI while resonant cascade schemes can give rise to self-pulsing LWI. The origin of this different behavior is discussed. For parameters of a real cascade system in atomic 138Ba we check numerically that the self-pulsing solution is stable in a broad range of nonzero detunings. It is shown that the self-pulsing emission can still be observed when the typical residual Doppler broadening of an atomic beam is taken into account.}, doi = {10.1103/PhysRevA.57.2163}, url = {http://link.aps.org/doi/10.1103/PhysRevA.57.2163}, author = {J. Mompart and C. Peters and R. Corbal{\'a}n} } @article {1355-5111-10-2-005, title = {Self-pulsing lasing without inversion in the double-Λ scheme}, journal = {Quantum and Semiclassical Optics: Journal of the European Optical Society Part B}, volume = {10}, number = {2}, year = {1998}, pages = {309}, abstract = {Lasing without inversion (LWI) is investigated from a nonlinear dynamics point of view for an atomic system with three coupled J = 0-1 transitions. The driving and generated fields couple two of these transitions defining a double- $\#$$\#$IMG$\#$$\#$ [http://ej.iop.org/images/1355-5111/10/2/005/img7.gif] scheme. In addition, two incoherent pump fields are acting on the system. We find that LWI can occur not only in a continuous wave regime but also in a self-pulsing regime. A clear physical interpretation of the origin of this self-pulsing LWI is given. We obtain analytically the threshold driving field intensity needed to achieve both continuous wave and self-pulsing LWI emission. For large enough cavity losses, the system can reach either continuous wave or self-pulsing regimes by only changing the driving field intensity.}, url = {http://stacks.iop.org/1355-5111/10/i=2/a=005}, author = {R. Corbal{\'a}n and J. Mompart and R. Vilaseca and E Arimondo} } @article {1355-5111-10-4-009, title = {Self-pulsing lasing without inversion in the double-Λ scheme}, journal = {Quantum and Semiclassical Optics: Journal of the European Optical Society Part B}, volume = {10}, number = {4}, year = {1998}, pages = {661}, abstract = {In this recently published article the address of the fourth author of this article was incorrectly stated. The correction affiliation for Professor Arimondo should read; Dipartimento di Fisica and Istituto Nazionale di Fisica della Materia, Unit{\'a} di Pisa, Universit{\'a} di Pisa, I-56100 Pisa, Italy.}, url = {http://stacks.iop.org/1355-5111/10/i=4/a=009}, author = {R. Corbal{\'a}n and J. Mompart and R. Vilaseca and E Arimondo} }