Papers by Maurizio Artoni
Applied Optics, 2001
Electromagnetically induced transparency is observed in a mismatched-wavelength cascade system wi... more Electromagnetically induced transparency is observed in a mismatched-wavelength cascade system with a room-temperature rubidium vapor cell. A cw probe laser beam monitors the 5S 1͞2 3 5P 3͞2 transition while another cw laser couples the 5P 3͞2 state to a higher excited state. The ratio of the observed Rabi frequencies for coupling to the 5P 3͞2 3 8D 3͞2 , 5͞2 transitions agrees well with that predicted by use of the transition oscillator strengths. Optical switching is demonstrated with an 80-mW coupling laser beam modulated up to 1 MHz.
European Physical Journal A, 2011
A semi-empirical model is presented for the excitation of collective nuclear resonances induced b... more A semi-empirical model is presented for the excitation of collective nuclear resonances induced by pions on nuclei in the [FORMULA](1232) energy region. The physical features of the collective states have been extracted according to the model by fitting data from a collection of resonant [FORMULA] -nucleus elastic scattering cross-sections. The contributions to the total binding energy and to the width of a collective state per each additional nucleon involved in the resonance have been extracted. The interaction between the collective resonances and the surrounding nuclear medium is discussed.
Atomic Coherence and its Potential Applications, 2009
Encyclopedia of Condensed Matter Physics, 2005
We present a scheme for the experimental realization of a quantum phase gate acting on the polari... more We present a scheme for the experimental realization of a quantum phase gate acting on the polarization degree of freedom of traveling single photon wave-packets. The scheme exploits the giant Kerr nonlinearities that can be achieved in dense atomic media showing electromagnetically induced transparency, and it may be useful in a variety of quantum communication schemes
Physical Review A, 1997
The electromagnetic field is quantized for normal transmission of incident waves through a parall... more The electromagnetic field is quantized for normal transmission of incident waves through a parallel-sided dielectric slab. The dielectric material is dispersive and it acts as a linear amplifier over limited ranges of the frequency and as a linear attenuator at the remaining frequencies. The field operators derived for the three spatial regions within and on either side of the slab are shown to satisfy the canonical commutation relations. The noise fluxes emitted by the slab are evaluated and shown to satisfy the general requirements for the minimum noise associated with linear amplifiers and attenuators. The behavior of the amplifier gain profile on the approach to the lasing threshold of the slab is determined, but the results are restricted to the belowthreshold state of the system. The spectra of the electric-field fluctuations are evaluated for the three spatial regions and for amplifying and attenuating frequencies. ͓S1050-2947͑97͒06402-0͔
Physical Review A, 1998
The quantum state of the electromagnetic field propagating in a nonstationary dielectric can acqu... more The quantum state of the electromagnetic field propagating in a nonstationary dielectric can acquire a phase shift that arises from modifications in the quantum fluctuations of the field. The shift could be observed, even for quite weak modifications, as a fringe displacement in an interference experiment.
Physical Review A, 2006
We analyze a four-wave mixing enhancement scheme based on a specific lifetime-broadened four-leve... more We analyze a four-wave mixing enhancement scheme based on a specific lifetime-broadened four-level atomic configuration. The enhancement can mainly be controlled through the time-dependent propagation dynamics of the applied pulse fields, but it is also found to depend on the sample density and spontaneous emission of the levels involved. A systematic analysis, that illustrates how the applied pulses dynamics, density, and spontaneous emission affect the mixing conversion efficiency, is carried out, anticipating substantially large efficiencies for realistic atomic parameters and short weak laser pulses.
Optics Communications, 1994
Phonons in a Iossless phonon-polariton exhibit remarkable non-classical features. In the small wa... more Phonons in a Iossless phonon-polariton exhibit remarkable non-classical features. In the small wavevectors side of the polariton energy spectrum, the phonon population in a phonon-polariton coherent state exhibits strong oscillations. This is caused by the highly non-classical structure of the phonon-polariton state in that region of the spectrum. A neutron scattering experiment enables one to probe the non-classical nature of a phonon-pelariton state.
The European Physical Journal D, 1998
We report on electromagnetically induced transparency in a radio-frequency discharge of metastabl... more We report on electromagnetically induced transparency in a radio-frequency discharge of metastable helium atoms. We show that a large effect can be observed in spite of the discharge regime needed to produce the metastable helium and in spite of its Zeeman degeneracy. We discuss the mechanism and the conditions for the observation of such a phenomenon in a helium discharge.
Even at absolute zero temperature the vibrating atoms in a solid undergo quantum fluctuations abo... more Even at absolute zero temperature the vibrating atoms in a solid undergo quantum fluctuations about their equilibrium positions. These fluctuations, alike the vacuum fluctuations of the electromagnetic field, constitute a fundamental limit to any measurement. We examine quantum states of the atomic displacement which allow for the possibility of modulating its quantum fluctuations below the zero-point motion level. Such squeezed
Springer Proceedings in Physics, 2001
Physical Review A, 2019
Efficient heralded generation of entanglement together with its manipulation is of great importan... more Efficient heralded generation of entanglement together with its manipulation is of great importance for quantum communications. In addition, states generated with bandwidths naturally compatible with atomic transitions allow a more efficient mapping of light into matter which is an essential requirement for long distance quantum communications. Here we propose a scheme where the indistinguishability between two spontaneous four-wave mixing processes is engineered to herald generation of single-photon frequency-bin entangled states, i.e. single-photons shared by two distinct frequency modes. We show that entanglement can be optimised together with the generation probability, while maintaining absorption negligible. Besides, the scheme illustrated for cold rubidium atoms is versatile and can be implemented in several other physical systems.
Physical Review A, 2017
Understanding the effects of disorder on the light propagation in photonic devices is of major im... more Understanding the effects of disorder on the light propagation in photonic devices is of major importance from both fundamental and applied points of view. Unidirectional reflectionless and coherent perfect absorption of optical signals are unusual yet fascinating phenomena that have recently sparked an extensive research effort in photonics. These two phenomena, which arise from topological deformations of the scattering matrix S parameters space, behave differently in the presence of different types of disorder, as we show here for a lossy photonic crystal prototype with a parity-time antisymmetric susceptibility or a more general non-Hermitian one.
Physical Review A, 2015
We study the interaction between a probe and a trigger weak fields in a sample of cold rubidium a... more We study the interaction between a probe and a trigger weak fields in a sample of cold rubidium atoms in the presence of a coupling and a dressing strong fields. Dipole Rydberg blockade may occur and can be set to depend on the probe and trigger polarizations giving rise to diverse regimes of electromagnetically induced transparency (EIT) with a concomitant small probe and trigger absorption and dispersion. This is shown to be relevant to the implementation of polarization conditional probe and trigger cross nonlinearities in cold Rydberg atoms.
Physical Review A, 2016
Wave propagation through rapidly but continuously varying media is surprisingly subtle, and in a ... more Wave propagation through rapidly but continuously varying media is surprisingly subtle, and in a pair of recent papers [
Nature Photonics, 2015
When a planar dielectric medium has a permittivity profile that is an analytic function in the up... more When a planar dielectric medium has a permittivity profile that is an analytic function in the upper or lower half of the complex position plane x = x + ix then the real and imaginary parts of its permittivity are related by the spatial Kramers-Kronig relations. We find that such a medium won't reflect radiation incident from one side, whatever the angle of incidence. Using the spatial Kramers-Kronig relations, one can derive a real part of a permittivity profile from some given imaginary part (or vice versa) such that the reflection is guaranteed to be zero. This result is valid for both scalar and vector wave theories, and may have relevance for designing materials that either efficiently absorb radiation, or for the creation of a new type of anti-reflection surface.
Physical Review A, 2015
Lossy atomic photonic crystals can be suitably tailored so that the real and imaginary parts of t... more Lossy atomic photonic crystals can be suitably tailored so that the real and imaginary parts of the susceptibility are, respectively, an odd and an even function of position. Such a parity-time (P T) space antisymmetry in the susceptibility requires neither optical gain nor negative refraction, but is rather attained by a combined control of the spatial modulation of both the atomic density and their dynamic level shift. These passive photonic crystals made of dressed atoms are characterized by a tunable unidirectional reflectionlessness accompanied by an appreciable degree of transmission. Interestingly, such peculiar properties are associated with non-Hermitian degeneracies of the crystal scattering matrix, which can then be directly observed through reflectivity measurements via a straightforward phase modulation of the atomic dynamic level shift and even off resonance.
Journal of Modern Optics, 2009
The photonic density of states of a light beam propagating through ultracold atoms may be easily ... more The photonic density of states of a light beam propagating through ultracold atoms may be easily modified by modulating the atomic susceptibility with a light grating. This was predicted and observed in a resonantly absorbing atomic sample supporting electromagnetically induced transparency where a probe nearly resonant with a standing wave coupling beam experiences a fully developed stop-band. In the present work, a probe that is resonant with higher harmonics of the standing wave frequency in a highly asymmetric three-level Ã-configuration or a ladder configuration, is predicted to exhibit a peculiar multipeak all-optically tunable reflection pattern. Such an unusual reflectivity spectrum is shown to be related to a suppression of the absorption akin to the Borrmann effect in the dynamical X-ray diffraction in crystals. This novel effect can actually be observed in atomic hydrogen but also in a variety of atoms, such as, for example, strontium, provided the optical lattice has been angle-tuned.
Physical Review A, 1998
We calculate the effects of normal transmission through an amplifying dielectric slab on the prop... more We calculate the effects of normal transmission through an amplifying dielectric slab on the properties of an incident pulse of light. The transmitted pulse shows shifts in peak position and additional lengthening or shortening with respect to the unamplified incident pulse. The magnitudes of these effects are generally larger than those of the corresponding changes that occur in transparent or attenuating slabs. They are interpreted in terms of the interference of multiply reflected contributions to the transmitted pulse. The theory is valid for pulses of nonclassical light, but the same reshaping occurs for appropriate pulses of classical light.
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Papers by Maurizio Artoni