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245 results on '"Di Trapani, Paolo"'

1. Space-time coupling in the up-conversion of broadband down-converted light

Author

Brambilla, Enrico, Jedrkiewicz, Ottavia, di Trapani, Paolo, and Gatti, Alessandra

Subjects
Physics - Optics
Abstract

We investigate the up-conversion process of broadband light from parametric down-conversion (PDC), focusing on the spatio-temporal spectral properties of the sum-frequency generated (SFG) radiation. We demonstrate that the incoherent component of the SFG spectrum is characterized by a skewed geometry in space-time, which originates from a compensation between the group-velocity mismatch and the spatial walk-off of the fundamental and the SFG fields. The results are illustrated both by a theoretical modeling of the optical system and by experimental measurements., Comment: 11 pages, 9 figures. arXiv admin note: text overlap with arXiv:1308.2366

Published
2014
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2. Spatiotemporal Amplitude and Phase Retrieval of Bessel-X pulses using a Hartmann-Shack Sensor

Author

Bonaretti, Fabio, Faccio, Daniele, Clerici, Matteo, Biegert, Jens, and Di Trapani, Paolo

Subjects
Physics - Optics
Abstract

We propose a new experimental technique, which allows for a complete characterization of ultrashort optical pulses both in space and in time. Combining the well-known Frequency-Resolved-Optical-Gating technique for the retrieval of the temporal profile of the pulse with a measurement of the near-field made with an Hartmann-Shack sensor, we are able to retrieve the spatiotemporal amplitude and phase profile of a Bessel-X pulse. By following the pulse evolution along the propagation direction we highlight the superluminal propagation of the pulse peak.

Published
2009
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3. Time-resolved refractive index and absorption mapping of light-plasma filaments in water

Author

Minardi, Stefano, Gopal, Amrutha, Tatarakis, Michael, Tamosauskas, Arnaud Couairon Gintaras, Piskarskas, Rimtautas, Dubietis, Audrius, and Di Trapani, Paolo

Subjects
Physics - Optics, Physics - Plasma Physics
Abstract

By means of a quantitative shadowgraphic method, we performed a space-time characterization of the refractive index variation and transient absorption induced by a light-plasma filament generated by a 100 fs laser pulse in water. The formation and evolution of the plasma channel in the proximity of the nonlinear focus were observed with a 23 fs time resolution., Comment: 3 pages, 3 pictures

Published
2007
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4. Three-dimensional vortex solitons in self-defocusing media

Author

Efremidis, Nikolaos K., Hizanidis, Kyriakos, Malomed, Boris A., and Di Trapani, Paolo

Subjects
Nonlinear Sciences - Pattern Formation and Solitons
Abstract

We demonstrate that families of vortex solitons are possible in a bi-dispersive three-dimensional nonlinear Schrodinger equation. These solutions can be considered as extensions of two-dimensional dark vortex solitons which, along the third dimension, remain localized due to the interplay between dispersion and nonlinearity. Such vortex solitons can be observed in optical media with normal dispersion, normal diffraction, and defocusing nonlinearity., Comment: 4 pages, 4 figures

Published
2007
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5. Collapse-driven spatiotemporal dynamics of filament formation

Author

Porras, Miguel A., Parola, Alberto, Faccio, Daniele, Couairon, Arnaud, and Di Trapani, Paolo

Subjects
Physics - Optics
Abstract

The transition from spatial to spatiotemporal dynamics in Kerr-driven beam collapse is modelled as the instability of the Townes profile. Coupled axial and conical radiation, temporal splitting and X waves appear as the effect of Y-shaped unstable modes, whose growth is experimentally detected., Comment: 4 pages, 3 figures

Published
2006

6. Conical emission, pulse splitting and X-wave parametric amplification in nonlinear dynamics of ultrashort light pulses

Author

Faccio, Daniele, Porras, Miguel A., Dubietis, Audrius, Bragheri, Francesca, Couairon, Arnaud, and Di Trapani, Paolo

Subjects
Physics - Optics
Abstract

The precise observation of the angle-frequency spectrum of light filaments in water reveals a scenario incompatible with current models of conical emission (CE). Its description in terms of linear X-wave modes leads us to understand filamentation dynamics requiring a phase- and group-matched, Kerr-driven four-wave-mixing process that involves two highly localized pumps and two X-waves. CE and temporal splitting arise naturally as two manifestations of this process.

Published
2005
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7. Far-field spectral characterization of conical emission and filamentation in Kerr media

Author

Faccio, Daniele, Di Trapani, Paolo, Minardi, Stefano, Bramati, Alberto, Bragheri, Francesca, Liberale, Carlo, Degiorgio, Vittorio, Dubietis, Audrius, and Matijosius, Aidas

Subjects
Physics - Optics
Abstract

By use of an imaging spectrometer we map the far-field ($\theta-\lambda$) spectra of 200 fs optical pulses that have undergone beam collapse and filamentation in a Kerr medium. By studying the evolution of the spectra with increasing input power and using a model based on stationary linear asymptotic wave modes, we are able to trace a consistent model of optical beam collapse high-lighting the interplay between conical emission, multiple pulse splitting and other effects such as spatial chirp., Comment: 8 pages, 9 figures

Published
2004
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8. Non-linear unbalanced Bessel beams: Stationary conical waves supported by nonlinear losses

Author

Porras, Miguel A., Parola, Alberto, Faccio, Daniele, Dubietis, Audrius, and Di Trapani, Paolo

Subjects
Physics - Optics, Physics - Classical Physics
Abstract

Nonlinear losses accompanying Kerr self-focusing substantially impacts the dynamic balance of diffraction and nonlinearity, permitting the existence of localized and stationary solutions of the 2D+1 nonlinear Schrodinger equation which are stable against radial collapse. These are featured by linear conical tails that continually refill the nonlinear, central spot. An experiment shows that the discovered solution behaves as strong attractor for the self-focusing dynamics in Kerr media., Comment: 4 pages, 2 figures; experimental verification added

Published
2004
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9. Light Filaments Without Self Guiding

Author

Dubietis, Audrius, Gaizauskas, Eugenijus, Tamosauskas, Gintaras, and Di Trapani, Paolo

Subjects
Physics - Optics
Abstract

An examination of the propagation of intense 200 fs pulses in water reveals light filaments not sustained by the balance between Kerr-induced self-focusing and plasma-induced defocusing. Their appearance is interpreted as the consequence of a spontaneous reshaping of the wave packet form a gaussian into a conical wave, driven by the requirement of maximum localization, minimum losses and stationarity in the presence of non-linear absorption., Comment: Submitted to Phys. Rev. Lett. on July 7th, 2003

Published
2003
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10. Localized and stationary light wave modes in dispersive media

Author

Porras, Miguel A. and Di Trapani, Paolo

Subjects
Physics - Optics
Abstract

In recent experiments, localized and stationary pulses have been generated in second-order nonlinear processes with femtosecond pulses, whose asymptotic features relate with those of nondiffracting and nondispersing polychromatic Bessel beams in linear dispersive media. We investigate on the nature of these linear waves, and show that they can be identified with the X-shaped (O-shaped) modes of the hyperbolic (elliptic) wave equation in media with normal (anomalous) dispersion. Depending on the relative strengths of mode phase mismatch, group velocity mismatch with respect to a plane pulse, and of the defeated group velocity dispersion, these modes can adopt the form of pulsed Bessel beams, focus wave modes, and X-waves (O-waves), respectively., Comment: 12 pages, 10 figures

Published
2003
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11. A compact, multi-pixel parametric light source

Author

Minardi, Stefano, Varanavicius, Arunas, Piskarskas, Algis, and Di Trapani, Paolo

Subjects
Physics - Optics
Abstract

The features of a compact, single pass, multi-pixel optical parametric generator are discussed. Several hundreds of independent high spatial-quality tunable ultrashort pulses were produced by pumping a bulk lithium triborate crystal with an array of tightly focussed intense beams. The array of beams was produced by shining a microlenses array with a large pump beam. Overall conversion efficiency to signal and idler up to 30% of the pump beam has been reported. Shot-to-shot energy fluctuation down to 3% was achieved for the generated radiation., Comment: 11 pages, 6 figures, submitted to "Optics Communications"

Published
2003
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12. Red solitons: evidence of spatio--temporal instability in $\chi^{(2)}$ spatial-soliton dynamics

Author

Minardi, Stefano, Blasi, Giovanni, Di Trapani, Paolo, Varanavicius, Arunas, Valiulis, Gintaras, Berzanskis, Audrius, and Piskarskas, Algis

Subjects
Physics - Optics, Physics - Fluid Dynamics
Abstract

In $\chi^{(2)}$ three-wave mixing, the noise-seeded spatio--temporal modulational instability has a dramatic impact on the spatial-soliton dynamics, leading to the counterintuitive observation of a soliton with no apparent participation of the high-frequency field in the process., Comment: 5 pages, 4 figures, submitted for publication

Published
2003
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23. Optimization of laser energy deposition for single-shot high aspect-ratio microstructuring of thick BK7 glass.

Author

Garzillo, Valerio, Jukna, Vytautas, Couairon, Arnaud, Grigutis, Robertas, Di Trapani, Paolo, and Jedrkiewicz, Ottavia

Subjects
LASER communication systems, INTEGRATED optics, ELECTRON glasses, OPTICAL instruments, MICROSTRUCTURE
Abstract

We investigate the generation of high aspect ratio microstructures across 0.7 mm thick glass by means of single shot Bessel beam laser direct writing. We study the effect on the photoinscription of the cone angle, as well as of the energy and duration of the ultrashort laser pulse. The aim of the study is to optimize the parameters for the writing of a regular microstructure due to index modification along the whole sample thickness. By using a spectrally resolved single pulse transmission diagnostics at the output surface of the glass, we correlate the single shot material modification with observations of the absorption in different portions of the retrieved spectra, and with the absence or presence of spectral modulation. Numerical simulations of the evolution of the Bessel pulse intensity and of the energy deposition inside the sample help us interpret the experimental results that suggest to use picosecond pulses for an efficient and more regular energy deposition. Picosecond pulses take advantage of nonlinear plasma absorption and avoid temporal dynamics effects which can compromise the stationarity of the Bessel beam propagation. [ABSTRACT FROM AUTHOR]

Published
2016
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24. Filamentary Deposition of Laser Energy in Glasses with Bessel Beams

Author

Lamperti, Massimo, Jukna, Vytautas, Jedrkiewicz, Ottavia, Di Trapani, Paolo, Stoian, Radic, Itina, Tatiana, XIE, CHEN, Courvoisier, François, Couairon, Arnaud, Centre de Physique Théorique [Palaiseau] (CPHT), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), University of Insubria (Dipartimento di Scienza e Alta Technologia), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Laser Research Center, Vilnius University [Vilnius], Istituto di Fotonica e Nanotecnologie, Laboratoire Hubert Curien [Saint Etienne] (LHC), and Université Jean Monnet [Saint-Étienne] (UJM)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS)

Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Physics::Optics
Abstract

International audience; The controlled laser energy deposition in dielectrics is a key technological issue for applications thatrequire drilling or structuring glass materials in the bulk. High angle Bessel beams delivered by a fem-tosecond laser have been used for extremely high aspect ratio nanochannels drilling and microstructuringin glass with a single laser shot [1,2]. Several types of filamentary damages were obtained with highangle Bessel beams and were reported to depend on laser pulse duration and energy [2]. I will addressthe question of optimal laser parameters for nonlinear absorption of laser energy in the bulk of dielectricmaterials, along the focal line of a Bessel beam.A semi-analytical model was developed for modeling the generation of a plasma column with fem-tosecond and picosecond laser pulses focused by a conical lens in dielectrics. The associated nonlinearabsorption of energy was calculated so as to highlight the influence of the pulse duration, laser pulseenergy and cone angle, on laser energy absorption. From a map of the density of nonlinear absorption oflaser energy in BK7 as a function of pulse duration and peak fluence, a specific pulse duration is shownto correspond to the highest nonlinear absorption at given pulse energy and cone angle. This durationcorresponds to a transition between two propagation regimes of the laser pulse featured by uniform ornon-uniform laser energy deposition in the Bessel zone. A uniform energy deposition is obtained in theabsence of pulse temporal dynamics.I will show that transmission measurements in BK7 are qualitatively well reproduced by the results ofthe semi-analytical model, which is also in agreement with numerical simulations of the nonlinear pulsepropagation

Published
2018

29. Superresonant Parametric Generation in Nonlinear Photonic Crystals

Author

Jedrkiewicz, Ottavia, Gatti, Alessandra, Brambilla, Enrico, Tamosauskas, Gintaras, Di Trapani, Paolo, Gallo, Katia, Jedrkiewicz, Ottavia, Gatti, Alessandra, Brambilla, Enrico, Tamosauskas, Gintaras, Di Trapani, Paolo, and Gallo, Katia

Abstract

Not duplicate with DiVA 1192859QC 20230206

Published
2017

36. Laser energy deposition in glasses with Bessel beams

Author

Couairon, Arnaud, Jukna, Vytautas, Minardi, Stefano, Jedrkiewicz, Ottavia, Selva, M., Lamperti, Massimo, Di Trapani, Paolo, Nikita, Shcheblanov, Itina, Tatiana, Stoian, Razvan, XIE, CHEN, Zhang, J., Dudley, John Michael, Courvoisier, François, Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Centre de Physique Théorique [Palaiseau] (CPHT), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Laboratoire Hubert Curien [Saint Etienne] (LHC), Université Jean Monnet [Saint-Étienne] (UJM)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS), Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche [Roma] (CNR), Neuroanesthesia, Fondazione IRCCS Istituto Neurologico 'Carlo Besta', Dipartimento di Scienza e Alta Technologia, Universitá degli Studi dell’Insubria, PIERS, and ANR-11-BS04-0010,NANOFLAM,Contrôle de la FiLAMentation et de la génération de plasma avec les impulsions non-diffractantes femtoseconde en régime nonlinéaire. Applications à la NANO-structuration laser à ultra haut rapport de forme.(2011)

Subjects
[PHYS]Physics [physics], [SPI]Engineering Sciences [physics], InformationSystems_GENERAL, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], GeneralLiterature_INTRODUCTORYANDSURVEY, ComputerApplications_MISCELLANEOUS, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, ComputingMilieux_MISCELLANEOUS, GeneralLiterature_MISCELLANEOUS
Abstract

International audience; Keynote talk

Published
2015

47. Filamentation with Bessel beams and Bessel vortices

Author

Couairon, Arnaud, Jukna, Vytautas, Milian, C., Arnold, Cord, Akturk, Selcuk, Mysyrowicz, André, Jedrkiewicz, Ottavia, Di Trapani, Paolo, Stoian, Razvan, Itina, Tatiana, XIE, CHEN, Giust, R, Ouadghiri, I., Dudley, John Michael, Courvoisier, François, Centre de Physique Théorique [Palaiseau] (CPHT), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Laboratoire Hubert Curien [Saint Etienne] (LHC), Université Jean Monnet [Saint-Étienne] (UJM)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS), Laboratoire d'optique appliquée (LOA), École Nationale Supérieure de Techniques Avancées (ENSTA Paris)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Istituto di Fotonica e Nanotecnologie, Consiglio Nazionale delle Ricerche [Roma] (CNR), Dipartimento di Scienza e Alta Technologia, Universitá degli Studi dell’Insubria, Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), International Symposium on Ultrafast Intense Laser Science, and ANR-11-BS04-0010,NANOFLAM,Contrôle de la FiLAMentation et de la génération de plasma avec les impulsions non-diffractantes femtoseconde en régime nonlinéaire. Applications à la NANO-structuration laser à ultra haut rapport de forme.(2011)

Subjects
[PHYS]Physics [physics], [SPI]Engineering Sciences [physics], [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2014

49. Disclosing the spatiotemporal structure of parametric down-conversion entanglement through frequency up-conversion

Author

Brambilla, Enrico, Jedrkiewicz, O., Lugiato, L. A., DI TRAPANI, Paolo, and Gatti, A.

Subjects
Physics, parametric down-conversion, Sum-frequency generation, Photon, business.industry, Inverse, Nonlinear Optics, Ultra-fast phenomenta, Spatio-temporal correlation, Quantum entanglement, quantum entanglement, 01 natural sciences, Atomic and Molecular Physics, and Optics, 010309 optics, Light intensity, Transverse plane, Optics, Spontaneous parametric down-conversion, sum frequency generation, 0103 physical sciences, Statistical physics, 010306 general physics, business, Parametric statistics
Abstract

In this work we propose and analyze a scheme where the full spatiotemporal correlation of twin photons or beams generated by parametric down-conversion is detected by using its inverse process, i.e., sum frequency generation. Our main result is that, by imposing independently a temporal delay Delta t and a transverse spatial shift Delta x between two twin components of PDC light, the up-converted light intensity provides information on the correlation of the PDC light in the full spatiotemporal domain and should enable the reconstruction of the peculiar X-shaped structure of the correlation predicted previously [A. Gatti et al. Phys. Rev. Lett. 102, 223601 (2009); L. Caspani et al. Phys. Rev. A 81, 033808 (2010); E. Brambilla et al. Phys. Rev. A 82, 013835 (2010)]. Through both a semianalytical and a numerical modeling of the proposed optical system, we analyze the feasibility of the experiment and identify the best conditions to implement it. In particular, the tolerance of the phase-sensitive measurement against the presence of dispersive elements, imperfect imaging conditions, and possible misalignments of the two crystals is evaluated.

Published
2012

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