51
51

Sep 22, 2013
09/13

by
Claudio Conti

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We study the affinities between the shape of the bright soliton of the one-dimensional nonlinear Schroedinger equation and that of the disorder induced localization in the presence of a Gaussian random potential. With emphasis on the focusing nonlinearity, we consider the bound states of the nonlinear Schroedinger equation with a random potential; for the state exhibiting the highest degree of localization, we derive explicit expressions for the nonlinear eigenvalue and for the localization...

Source: http://arxiv.org/abs/1210.0002v1

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6.0

Jun 30, 2018
06/18

by
Claudio Conti

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We show that an analog of the physics at the Planck scale can be found in the propagation of tightly focused laser beams. Various equations that occur in generalized quantum mechanics are formally identical to those describing the nonlinear nonlocal propagation of nonparaxial laser beams. The analysis includes a generalized uncertainty principle and shows that the nonlinear focusing of a light beam with dimensions comparable to the wavelength corresponds to the spontaneous excitation of the...

Topics: Physics, High Energy Physics - Theory, Nonlinear Sciences, Quantum Physics, Optics, Pattern...

Source: http://arxiv.org/abs/1406.6677

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48

Sep 22, 2013
09/13

by
Claudio Conti

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In the framework of the paraxial and of the slowly varying envelope approximations, with reference to a normally dispersive medium or to vacuum, the electromagnetic field is given as a continuous quantum superposition of non-dispersive and non-diffracting wave-packets (namely X-waves). Entangled states as pairs of elementary excitations traveling at (approximately) the same velocity are found in optical parametric amplification.

Source: http://arxiv.org/abs/quant-ph/0309069v3

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47

Sep 22, 2013
09/13

by
Claudio Conti

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We investigate the dynamics of a Bose-Einstein condensate in a progressively bended three dimensional cigar shaped potential. The interplay between geometry and nonlinearity is considered. At high curvature, topological localization occurs and becomes frustrated by the generation of curved dispersive shock-waves when the strength of nonlinearity is increased. The analysis is supported by four-dimensional parallel simulations.

Source: http://arxiv.org/abs/1302.3806v3

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96

Sep 22, 2013
09/13

by
Claudio Conti

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A quantum theory of 3D X-shaped optical bullets in Kerr media is presented. The existence of progressive undistorted squeezed vacuum is predicted. Applications to quantum non-demolition experiments, entanglement and interferometers for gravitational waves detection are envisaged.

Source: http://arxiv.org/abs/quant-ph/0409130v1

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62

Sep 20, 2013
09/13

by
Claudio Conti

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The generation of finite energy packets of X-waves is analysed in normally dispersive cubic media by using an X-wave expansion. The 3D nonlinear Schroedinger model is reduced to a 1D equation with anomalous dispersion. Pulse splitting and beam replenishment as observed in experiments with water and Kerr media are explained in terms of a higher order breathing soliton. The results presented also hold in periodic media and Bose-condensed gases.

Source: http://arxiv.org/abs/physics/0404022v3

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84

Sep 23, 2013
09/13

by
Claudio Conti

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We investigate a special class of cellular automata (CA) evolving in a environment filled by an electromagnetic wave. The rules of the Conway's Game of Life are modified to account for the ability to retrieve life-sustenance from the field energy. Light-induced self-structuring and self-healing abilities and various dynamic phases are displayed by the CA. Photo-driven genetic selection and the nonlinear feedback of the CA on the electromagnetic field are included in the model, and there are...

Source: http://arxiv.org/abs/0810.3179v2

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53

Sep 24, 2013
09/13

by
Claudio Conti

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The dynamics of several light filaments (spatial optical solitons) propagating in an optically nonlinear and non-local random medium is investigated using the paradigms of the physics of complexity. Cluster formation is interpreted as a dynamic phase transition. A connection with the random matrices approach for explaining the vibrational spectra of an ensemble of solitons is pointed out. General arguments based on a Brownian dynamics model are validated by the numerical simulation of a...

Source: http://arxiv.org/abs/physics/0412051v3

4
4.0

Apr 4, 2021
04/21

by
CLAUDIO CONTI (furb3tto)

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Tappi per il telaio Hypermotard 950. Sono stati progettati per non aver bisogno di supporti, quando li posizionate sul piano di stampa ricordatevi di tenere il logo non a contatto con il letto di stampa.

Topics: thingiverse, Machine Tools, stl

8
8.0

Mar 15, 2021
03/21

by
CLAUDIO CONTI (furb3tto)

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Non avendo trovato nulla che mi piacesse a livello di design, ho progettato questo case per ascoltare la musica liquida. Incorpora un amplificatore e monitor 5" touch. Ho poi aggiunto un termostato e una ventola per quando ci saranno giornate molto calde considerando che io non lo spengo mai ma metto in pausa la canzone così dopo pochi minuti anche il display va in standby. Ho inserito alcune foto con i rendering iniziali e il progetto terminato. ho inserito anche un file di testo con...

Topics: stl, Audio, thingiverse

3
3.0

Jun 29, 2018
06/18

by
Laura Pilozzi; Claudio Conti

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The use of virtually lossless topologically isolated edge states may lead to a novel class of thresholdless lasers operating without inversion. One needs however to understand if topological states may be coupled to external radiation and act as active cavities. We study a two-level topological insulator and show that self-induced transparency pulses can directly excite edge states. We simulate laser emission by a suitable designed topological cavity, and show that it can emit tunable...

Topics: Mesoscale and Nanoscale Physics, Optics, Condensed Matter, Physics

Source: http://arxiv.org/abs/1602.06782

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63

Sep 18, 2013
09/13

by
Alessandro Ciattoni; Claudio Conti

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We show that two distinct quantum states of the electromagnetic field can be associated to a classical vector X wave or a propagation-invariant solution of Maxwell equations. The difference between the two states is of pure quantum mechanical origin since they are internally entangled and disentangled, respectively and can be generated by different linear or nonlinear processes. Detection and generation of Schr\"odinger-cat states comprising two entangled X-waves and their possible...

Source: http://arxiv.org/abs/0704.0442v1

56
56

Sep 22, 2013
09/13

by
Claudio Conti; Stefano Trillo

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We predict that an ultra-cold Bose gas in an optical lattice can give rise to a new form of condensation, namely matter X waves. These are non-spreading 3D wave-packets which reflect the symmetry of the Laplacian with a negative effective mass along the lattice direction, and are allowed to exist in the absence of any trapping potential even in the limit of non-interacting atoms. This result has also strong implications for optical propagation in periodic structures

Source: http://arxiv.org/abs/physics/0308051v1

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50

Sep 20, 2013
09/13

by
Claudio Conti; Andrea Fratalocchi

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We report on 3D time-domain parallel simulations of Anderson localization of light in inverted disordered opals displaying a complete photonic band-gap. We investigate dynamic diffusion processes induced by femtosecond laser excitations, calculate the diffusion constant and the decay-time distribution versus the strength of the disorder. We report evidence of the transition from delocalized Bloch oscillations to strongly localized resonances in self-starting laser processes.

Source: http://arxiv.org/abs/0802.3775v1

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64

Sep 21, 2013
09/13

by
Claudio Conti; Stefano Trillo

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In the theory of optical gap solitons, slowly-moving finite-amplitude Lorentzian solutions are found to mediate the transition from bright to coexistent dark-antidark solitary wave pairs when the laser frequency is detuned out of the proper edge of a dynamical photonic bandgap. Catastrophe theory is applied to give a geometrical description of this strongly asymmetrical 'morphing' process.

Source: http://arxiv.org/abs/physics/0104042v1

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109

Jul 19, 2013
07/13

by
Marco Leonetti; Claudio Conti

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We report on experimental tests of the trend of random laserlinewidth versus pumping power as predicted by an Haus master equation that is formally identical to the one-dimensional Gross- Pitaevskii equation in an harmonic potential. Experiments are done by employing picosecond pumped dispersions of Titaniumdioxide particles in dye-doped methanol. The derivation of the master equations is also detailed and shown to be in agreement with experiments analytically predicting the value of the...

Source: http://arxiv.org/abs/1005.2082v1

58
58

Sep 18, 2013
09/13

by
Viola Folli; Claudio Conti

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The effect of focusing and defocusing nonlinearities on Anderson localization in highly nonlocal media is theoretically and numerically investigated. A perturbative approach is developed to solve the nonlocal nonlinear Schroedinger equation in the presence of a random potential, showing that nonlocality stabilizes Anderson states.

Source: http://arxiv.org/abs/1201.3923v1

3
3.0

Jun 30, 2018
06/18

by
Nicola Bulso; Claudio Conti

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We investigate beam diffraction and spatial modulation instability of coherent light beams propagating in the non-paraxial regime in a nonlinear Kerr medium. We study the instability of plane wave solutions in terms of the degree of non-paraxiality, beyond the regime of validity of the nonlinear Schroedinger equation. We also numerically analyze the way non-paraxial terms breaks the integrability and affect the periodical evolution of higher order soliton solutions. We discuss non-locality and...

Topics: Physics, Nonlinear Sciences, Optics, Pattern Formation and Solitons

Source: http://arxiv.org/abs/1402.1161

5
5.0

Jun 30, 2018
06/18

by
Claudio Conti; Robert Boyd

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A transparent material exhibits ultra-fast optical nonlinearity and is subject to optical pressure if irradiated by a laser beam. However, the effect of nonlinearity on optical pressure is often overlooked, even if a nonlinear optical pressure may be potentially employed in many applications, as optical manipulation, biophysics, cavity optomechanics, quantum optics, optical tractors, and is relevant in fundamental problems as the Abraham-Minkoswky dilemma, or the Casimir effect. Here we show...

Topics: Physics, Quantum Physics, Optics

Source: http://arxiv.org/abs/1403.1948

5
5.0

Jun 30, 2018
06/18

by
Silvia Gentilini; Claudio Conti

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Using light to control the movement of nano-structured objects is a great challenge. This challenge involves fields like optical tweezing, Casimir forces, integrated optics, bio-physics, and many others. Photonic "robots" could have uncountable applications. However, if the complexity of light-activated devices increases, structural disorder unavoidably occurs and, correspondingly, light scattering, diffusion and localization. Are optically-driven mechanical forces affected by...

Topics: Physics, Optics

Source: http://arxiv.org/abs/1410.1919

58
58

Sep 21, 2013
09/13

by
Claudio Conti; Eugenio DelRe

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We investigate theoretically, numerically and experimentally nonlinear optical waves in an absorbing out-of-equilibrium colloidal material at the gelification transition. At sufficiently high optical intensity, absorption is frustrated and light propagates into the medium. The process is mediated by the formation of a matter-shock wave due to optically induced thermodiffusion, and largely resembles the mechanism of hydrodynamical supercavitation, as it is accompanied by a dynamic...

Source: http://arxiv.org/abs/1008.2616v2

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37

Jul 19, 2013
07/13

by
Viola Folli; Claudio Conti

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We investigate the evolution of solitary waves in a nonlocal medium in the presence of disorder. By using a perturbational approach, we show that an increasing degree of nonlocality may largely hamper the Brownian motion of self-trapped wave-packets. The result is valid for any kind of nonlocality and in the presence of non-paraxial effects. Analytical predictions are compared with numerical simulations based on stochastic partial differential equation

Source: http://arxiv.org/abs/1005.0578v1

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41

Sep 18, 2013
09/13

by
Viola Folli; Claudio Conti

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Self-induced transparency pulses propagating in a random medium embedded in a two-level system can transfer energy to localized Anderson states. This allows the onset of two-level laser-like action.

Source: http://arxiv.org/abs/1102.1207v2

48
48

Sep 19, 2013
09/13

by
Claudio Conti; Luca Leuzzi

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The statistical properties of the phases of several modes nonlinearly coupled in a random system are investigated by means of a Hamiltonian model with disordered couplings. The regime in which the modes have a stationary distribution of their energies and the phases are coupled is studied for arbitrary degrees of randomness and energy. The complexity versus temperature and strength of nonlinearity is calculated. A phase diagram is derived in terms of the stored energy and amount of disorder....

Source: http://arxiv.org/abs/1009.3290v1

6
6.0

Jun 29, 2018
06/18

by
Giulia Marcucci; Claudio Conti

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It is well known that a state with complex energy cannot be the eigenstate of a self-adjoint operator, like the Hamiltonian. Resonances, i.e. states with exponentially decaying observables, are not vectors belonging to the conventional Hilbert space. One can describe these resonances in an unusual mathematical formalism, based on the so-called Rigged Hilbert Space (RHS). In the RHS, the states with complex energy are denoted as Gamow Vectors (GV), and they model decay processes. We study GV of...

Topics: Physics, Quantum Physics, Mathematical Physics, Optics, Mathematics

Source: http://arxiv.org/abs/1607.08109

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5.0

Jun 30, 2018
06/18

by
Marcello Calvanese Strinati; Claudio Conti

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We consider a microcavity made by a graded-index (GRIN) glass, doped by dye molecules, placed within two planar mirrors and study Bose-Einstein condensation (BEC) of photons. The presence of the mirrors leads to an effective photon mass, and the index grading provides an effective trapping frequency; the photon gas becomes formally equivalent to a two dimensional Bose gas trapped in an isotropic harmonic potential. The inclusion of nonlinear effects provides an effective interaction between...

Topics: Physics, Nonlinear Sciences, Quantum Gases, Optics, Pattern Formation and Solitons, Condensed Matter

Source: http://arxiv.org/abs/1406.6250

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43

Sep 20, 2013
09/13

by
Marco Leonetti; Claudio Conti; Cefe Lopez

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We show that the degree of localization for the modes of a random laser (RL) is affected by the inter mode interaction that is controlled by shaping the spot of the pump laser. By experimentally investigating the spatial properties of the lasing emission we infer that strongly localized modes are activated in the low interacting regime while in the strongly interacting one extended modes are found lasing. Thus we demonstrate that the degree o localization may be finely tuned at the micrometer...

Source: http://arxiv.org/abs/1207.4181v1

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44

Sep 18, 2013
09/13

by
Viola Folli; Eugenio DelRe; Claudio Conti

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The instabilities arising in a one-dimensional beam sustained by the diffusive photorefractive nonlinearity in out-of-equilibrium ferroelectrics are theoretically and numerically investigated. In the "scale-free model", in striking contrast with the well-known spatial modulational instability, two different beam instabilities dominate: a defocusing and a fragmenting process. Both are independent of the beam power and are not associated to any specific periodic pattern.

Source: http://arxiv.org/abs/1201.3865v1

16
16

Jun 27, 2018
06/18

by
Marco Ornigotti; Claudio Conti; Alexander Szameit

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We introduce a new class of nondiffracting optical pulses possessing orbital angular momentum. By generalizing the X-waves solution of the Maxwell equation, we discover the coupling between angular momentum and the temporal degrees of freedom of ultra-short pulses. The spatial twist of propagation invariant light pulse turns out to be directly related to the number of optical cycles. Our results may trigger the development on novel multi-level classical and quantum transmission channels free of...

Topics: Optics, Physics

Source: http://arxiv.org/abs/1503.02979

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92

Jun 30, 2018
06/18

by
Marco Ornigotti; Claudio Conti; Alexander Szameit

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We present a complete and consistent quantum theory of generalised X waves with orbital angular momentum (OAM) in dispersive media. We show that the resulting quantised light pulses are affected by neither dispersion nor diffraction and are therefore resilient against external perturbations. The nonlinear interaction of quantised X waves in quadratic and Kerr nonlinear media is also presented and studied in detail.

Topics: Optics, Physics, Quantum Physics

Source: http://arxiv.org/abs/1704.07258

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71

Jul 20, 2013
07/13

by
Marco Leonetti; Claudio Conti; Cefe Lopez

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Controlling the flow of energy in a random medium is a research frontier with a wide range of applications. As recently demonstrated, the effect of disorder on the transmission of optical beams, may be partially compensated by wavefront shaping, but losing control over individual light paths. Here we report on a novel physical effect whereby energy is spatially and spectrally transferred inside a disordered active medium by the coupling between individual lasing modes. We show that is possible...

Source: http://arxiv.org/abs/1304.8002v1

5
5.0

Jun 30, 2018
06/18

by
Marco Ornigotti; Andrea Aiello; Claudio Conti

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We present a theoretical analysis for the \GH and \IF shifts experienced by an X-wave upon reflection from a dielectric interface. We show that the temporal chirp, as well as the bandwidth of the X-wave directly affect the spatial shifts in a way that can be experimentally observed, while the angular shifts do not depend on the spectral features of the X-Wave. A dependence of the spatial shifts on the spatial structure of the X-wave is also discussed.

Topics: Physics, Optics

Source: http://arxiv.org/abs/1411.2376

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54

Jul 20, 2013
07/13

by
Neda Ghofraniha; Claudio Conti; Giancarlo Ruocco

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Using Z-scan and dynamic light scattering measurements we investigate the nonlinear optics response of a colloidal solution undergoing dynamics slowing down with age. We study the high optical nonlinearity of an organic dye (Rhodamine B) dispersed in a water-clay (Laponite) solution, at different clay concentrations (2.0 wt% - 2.6 wt%), experiencing the gelation process. We determine the clay platelets self diffusion coefficient and, by its comparison with the structural relaxation time, we...

Source: http://arxiv.org/abs/cond-mat/0609659v1

3
3.0

Jun 30, 2018
06/18

by
Andrea Armaroli; Claudio Conti; Fabio Biancalana

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Non-deterministic giant waves, denoted as rogue, killer, monster or freak waves, have been reported in many different branches of physics. Their origin is however still unknown: despite the massive numerical and experimental evidence, the ultimate reason for their spontaneous formation has not been identified yet. Here we show that rogue waves in optical fibres actually result from a complex dynamic process very similar to well known mechanisms such as glass transitions and protein folding. We...

Topics: Physics, Nonlinear Sciences, Disordered Systems and Neural Networks, Pattern Formation and...

Source: http://arxiv.org/abs/1406.5966

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94

Sep 17, 2013
09/13

by
Claudio Conti; Andrea Fratalocchi; Silvia Gentilini

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We investigate Anderson localization of light as occurring in ultra-short excitations. A theory based on time dependent coupled-mode equations predicts universal features in the spectrum of the transmitted pulse. In particular, the process of strong localization of light is shown to correspond to the formation of peaks in both the amplitude and in the group delay of the transmitted pulse. Parallel ab-initio simulations made with Finite-Difference Time Domain codes and molecular dynamics confirm...

Source: http://arxiv.org/abs/1003.2555v1

3
3.0

Jun 29, 2018
06/18

by
Marco Ornigotti; Claudio Conti; Alexander Szameit

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We extend the concept of radially and azimuthally polarized optical beams to the polychromatic domain by introducing cylindrically polarized nondiffracting optical pulses. In particular, we discuss in detail the case of cylindrically polarized X-waves, both in the paraxial and nonparaxial regime. The explicit expressions for the electric and magnetic fields of cylindrically polarized X-waves is also reported.

Topics: Optics, Physics

Source: http://arxiv.org/abs/1602.03317

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48

Sep 20, 2013
09/13

by
Claudio Conti; Luca Angelani; Giancarlo Ruocco

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Using a 3D Finite-Difference Time-Domain parallel code, we report on the linear and nonlinear propagation of light pulses in a disordered assembly of scatterers, whose spatial distribution is generated by a Molecular Dynamics code; refractive index dispersion is also taken into account. We calculate the static and dynamical diffusion constant of light, while considering a pulsed excitation. Our results are in quantitative agreement with reported experiments, also furnishing evidence of a...

Source: http://arxiv.org/abs/cond-mat/0607534v3

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113

Jul 20, 2013
07/13

by
Marco Leonetti; Claudio Conti; Cefe Lopez

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The discovery of the spontaneous mode-locking of lasers, i.e., the synchronous oscillation of electromagnetic modes in a cavity, has been a milestone of photonics allowing the realization of oscillators delivering ultra-short pulses. This process is so far known to occur only in standard ordered lasers with meter size length and only in the presence of a specific device (the saturable absorber). Here we demonstrate that mode-locking can spontaneously arise also in random lasers composed by...

Source: http://arxiv.org/abs/1304.3652v1

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66

Jul 20, 2013
07/13

by
Haiming Dong; Claudio Conti; Fabio Biancalana

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We propose an electrically tunable graphene-based metamaterial showing a large nonlinear optical response at THz frequencies, which we calculate analytically for the first time to our knowledge and arises from the intraband current. The structure sustains a novel type of stable two-dimensional spatial solitary wave, a relativistic version of the Townes soliton. These results can be also applied to any material exhibiting a conical dispersion with massless Dirac fermions.

Source: http://arxiv.org/abs/1107.5803v1

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58

Sep 23, 2013
09/13

by
Claudio Conti; Giancarlo Ruocco; Stefano Trillo

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We predict that spatial self-trapping of light can occur in soft matter encompassing a wide class of new materials such as colloids, foams, gels, fractal aggregates etc. We develop a general nonlocal theory that allows to relate the properties of the trapped state of Maxwell equations to the measurable static structure factor of the specific material. We give numerical evidence for stable trapping in fractal aggregates and suggest also the possibility of soliton spectroscopy of soft-matter.

Source: http://arxiv.org/abs/physics/0510172v1

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46

Sep 22, 2013
09/13

by
Claudio Conti; Marco Peccianti; Gaetano Assanto

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We develop a general theory of spatial solitons in a liquid crystalline medium exhibiting a nonlinearity with an arbitrary degree of effective nonlocality. The model accounts the observability of "accessible solitons" and establishes an important link with parametric solitons.

Source: http://arxiv.org/abs/physics/0308024v1

4
4.0

Jun 30, 2018
06/18

by
Silvia Gentilini; Eugenio DelRe; Claudio Conti

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We investigate the effect of non-paraxiality in the dynamics of dispersive shock waves in the defocusing nonlinear Schroedinger equation. We show that the problem can be described in terms of a relativistic particle moving in a potential. Lowest order corrections enhance the wave-breaking and impose a limit to the highest achievable spectrum in an amount experimentally testable.

Topics: Physics, Optics

Source: http://arxiv.org/abs/1412.8602

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4.0

Jun 29, 2018
06/18

by
Maria Chiara Braidotti; Silvia Gentilini; Claudio Conti

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The description of shock waves beyond the shock point is a challenge in nonlinear physics. Finding solutions to the global dynamics of dispersive shock waves is not always possible due to the lack of integrability. Here we propose a new method based on the eigenstates (Gamow vectors) of a reversed harmonic oscillator in a rigged Hilbert space. These vectors allow analytical formulation for the development of undular bores of shock waves in a nonlinear nonlocal medium. Experiments by a...

Topics: Pattern Formation and Solitons, Nonlinear Sciences, Optics, Physics

Source: http://arxiv.org/abs/1601.05796

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56

Sep 18, 2013
09/13

by
Claudio Conti; Aharon J. Agranat; Eugenio DelRe

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We predict the existence of a novel class of multidimensional light localizations in out-of-equilibrium ferroelectric crystals. In two dimensions, the non-diffracting beams form at arbitrary low power level and propagate even when their width is well below the optical wavelength. In three dimensions, a novel form of subwavelength light bullets is found. The effects emerge when compositionally disordered crystals are brought to their metastable glassy state, and can have a profound impact on...

Source: http://arxiv.org/abs/1102.4945v1

7
7.0

Jun 29, 2018
06/18

by
Mohammed F. Saleh; Claudio Conti; Fabio Biancalana

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We unveil the relation between the linear Anderson localisation process and nonlinear modulation instability. Anderson localised modes are formed in certain temporal intervals due to the random background noise. Such localised modes seed the formation of solitary waves that will appear during the modulation instability process at those preferred intervals. Afterwards, optical-event horizon effects between dispersive waves and solitons produce an artificial collective acceleration that favours...

Topics: Optics, Physics

Source: http://arxiv.org/abs/1610.01813

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72

Sep 20, 2013
09/13

by
Bruno Crosignani; Paolo Di Porto; Claudio Conti

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The limits of the Second Law of Thermodynamics, which reigns undisputed in the macroscopic world, are investigated at the mesoscopic level, corresponding to spatial dimensions of a few microns. An extremely simple isolated system, modeled after Callen's adiabatic piston, [1] can, under appropriate conditions, be described as a self-organizing Brownian motor and shown to exhibit a perpetuum mobile behavior.

Source: http://arxiv.org/abs/physics/0410050v2

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55

Sep 19, 2013
09/13

by
Andrea Di Falco; Claudio Conti; Gaetano Assanto

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We analyze phase matching with reference to frequency doubling in nanosized quadratic waveguides encompassing form birefringence and supporting cross-polarized fundamental and second-harmonic modes. In an AlGaAs rod with an air void, we show that phase-matched second-harmonic generation could be achieved in a wide spectral range employing state-of-the-art nanotechnology.

Source: http://arxiv.org/abs/physics/0610158v1

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47

Sep 22, 2013
09/13

by
Andrea Di Falco; Claudio Conti; Gaetano Assanto

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Using a 3D fully-vectorial nonlinear time-domain analysis we numerically investigate the generation of terahertz radiation by pumping a photonic crystal microcavity out of resonance. High quality factors and a quadratic susceptibility lead to few-cycle terahertz pulses via optical rectification. Material dispersion as well as linear and nonlinear anisotropy is fully accounted for.

Source: http://arxiv.org/abs/physics/0501065v1

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49

Sep 22, 2013
09/13

by
Claudio Conti; Andrea Di Falco; Gaetano Assanto

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We investigate optical parametric oscillations through four-wave mixing in resonant cavities and photonic crystals. The theoretical analysis underlines the relevant features of the phenomenon and the role of the density of states. Using fully vectorial 3D time-domain simulations, including both dispersion and nonlinear polarization, for the first time we address this process in a face centered cubic lattice and in a photonic crystal slab. The results lead the way to the development of novel...

Source: http://arxiv.org/abs/physics/0403013v1

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40

Sep 21, 2013
09/13

by
Andrea Fratalocchi; Claudio Conti; Giancarlo Ruocco; Stefano Trillo

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We investigate the dynamics of a gas of non-interacting particle-like soliton waves, demonstrating that phase transitions originate from their collective behavior. This is predicted by solving exactly the nonlinear equations and by employing methods of the statistical mechanics of chaos. In particular, we show that a suitable free energy undergoes a metamorphosis as the input excitation is increased, thereby developing a first order phase transition whose measurable manifestation is the...

Source: http://arxiv.org/abs/0808.0882v1