Search results for " Optics"
showing 10 items of 5880 documents
Supercontinuum Generation in Tellurite Optical Fibers
2017
This chapter presents a state of the art of infrared supercontinuum generation in heavy oxide tellurite optical fibers from the experimental results published by the international community. As a first part, a bibliographic table gathers the literature on which this work is based. Then, the second part briefly returns on the tellurite glass compositions, the third part presents the different fiber structures (microstructured, suspended core or step-index fibers, tapered fibers), the fourth part discusses the pumping sources in relation with the fiber chromatic dispersion as well as coupling issues, the supercontinuum performances are presented in the fifth part, and the sixth part deals wit…
Effectiveness of nonlinear optical loop mirrors in chirped fiber gratings compensated dispersion-managed transmission systems
2005
International audience; We show that nonlinear optical loop mirrors can dramatically suppress the side peaks induced by the group delay ripples in chirped fiber gratings compensated dispersion-managed systems and significantly improve the system performance.
Modulational instability and domain wall solitons in optical fibers
2000
The first part of this thesis presents some theoretical and experimental results about modulational instability and domain wall solitons in bimodal fibers.In the second part is devoted to the interaction of counter-propagating waves in an isotropic optical fiber
Strongly confined atomic localization by Rydberg coherent population trapping
2020
In this letter we investigate the possibility to attain strongly confined atomic localization using interacting Rydberg atoms in a Coherent Population Trapping (CPT) ladder configuration, where a standing-wave (SW) is used as a coupling field in the second leg of the ladder. Depending on the degree of compensation of the Rydberg level energy shift induced by the van der Waals (vdW) interaction, by the coupling field detuning, we distinguish between two antiblockade regimes, i.e. a partial antiblockade (PA) and a full antiblockade (FA). While a periodic pattern of tightly localized regions can be achieved for both regimes, the PA allows much faster converge of spatial confinement yielding a …
Ultraprecise Rydberg atomic localization using optical vortices
2020
We propose a robust localization of the highly-excited Rydberg atoms, interacting with doughnut-shaped optical vortices. Compared with the earlier standing-wave (SW)-based localization methods, a vortex beam can provide an ultrahigh-precision two-dimensional localization solely in the zero-intensity center, within a confined excitation region down to the nanometer scale. We show that the presence of the Rydberg-Rydberg interaction permits counter-intuitively much stronger confinement towards a high spatial resolution when it is partially compensated by a suitable detuning. In addition, applying an auxiliary SW modulation to the two-photon detuning allows a three-dimensional confinement of R…
Crystal field calculations of energy levels of the Ni2+ ions in MgO
2013
Abstract The electronic energy levels of six-fold coordinated Ni 2+ ion in magnesium oxide MgO were calculated using the exchange charge model of crystal field theory. The calculated energetic positions of the Ni 2+ levels match well the experimental spectrum. Inclusion of the spin-orbit (SO) interaction is compulsory to account for the first excited 3 T 2g state fine structure; however, it does not explain why out of four levels arising from the 3 T 2g state, only two are seen in the experimental spectra. One possible explanation to this fact can be advanced by invoking the Jahn–Teller effect.
Entanglement detection in hybrid optomechanical systems
2011
We study a device formed by a Bose Einstein condensate (BEC) coupled to the field of a cavity with a moving end-mirror and find a working point such that the mirror-light entanglement is reproduced by the BEC-light quantum correlations. This provides an experimentally viable tool for inferring mirror-light entanglement with only a limited set of assumptions. We prove the existence of tripartite entanglement in the hybrid device, persisting up to temperatures of a few milli-Kelvin, and discuss a scheme to detect it.
Cold-Atom-Induced Control of an Optomechanical Device
2010
We consider a cavity with a vibrating end mirror and coupled to a Bose-Einstein condensate. The cavity field mediates the interplay between mirror and collective oscillations of the atomic density. We study the implications of this dynamics and the possibility of an indirect diagnostic. Our predictions can be observed in a realistic setup that is central to the current quest for mesoscopic quantumness.
Dissipative solitons for mode-locked lasers
2012
International audience; Dissipative solitons are localized formations of an electromagnetic field that are balanced through an energy exchange with the environment in presence of nonlinearity, dispersion and/or diffraction. Their growing use in the area of passively mode-locked lasers is remarkable: the concept of a dissipative soliton provides an excellent framework for understanding complex pulse dynamics and stimulates innovative cavity designs. Reciprocally, the field of mode-locked lasers serves as an ideal playground for testing the concept of dissipative solitons and revealing their unusual dynamics. This Review provides basic definitions of dissipative solitons, summarizes their imp…
Coherent Control of Stimulated Emission inside one dimensional Photonic Crystals:Strong Coupling regime
2006
The present paper discusses the stimulated emission, in strong coupling regime, of an atom embedded inside a one dimensional (1D) Photonic Band Gap (PBG) cavity which is pumped by two counter-propagating laser beams. Quantum electrodynamics is applied to model the atom-field interaction, by considering the atom as a two level system, the e.m. field as a superposition of normal modes, the coupling in dipole approximation, and the equations of motion in Wigner-Weisskopf and rotating wave approximations. In addition, the Quasi Normal Mode (QNM) approach for an open cavity is adopted, interpreting the local density of states (LDOS) as the local density of probability to excite one QNM of the ca…