Daniele Faccio

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The ability to record images with extreme temporal resolution enables a diverse range of applications, such as fluorescence lifetime imaging, time-of-flight depth imaging and characterization of ultrafast processes. Recently, ultrafast imaging schemes have emerged, which require either long acquisition times or raster scanning and have a requirement for(More)
Event horizons of astrophysical black holes and gravitational analogues have been predicted to excite the quantum vacuum and give rise to the emission of quanta, known as Hawking radiation. We experimentally create such a gravitational analogue using ultrashort laser pulse filaments and our measurements demonstrate a spontaneous emission of photons that(More)
We investigate the formation of X waves during filamentation in Kerr media. From the standard model developed for femtosecond filamentation in liquids, solids, and gases, the influence of several physical effects and parameters is numerically studied in the strongly nonlinear regime where group velocity dispersion alone is insufficient to arrest collapse.(More)
We demonstrate efficient optical parametric amplification and generation in a gas-filled hollow-core fiber of near-infrared pulses, peaked at 1.4 microm wavelength, with 5 microJ energy and 45 fs duration at the fiber output. Numerical simulations confirm that the OPA is phase matched through excitation of higher-order fiber modes.
We report on highly efficient four-wave optical parametric amplification in a water cell pumped by an elliptically shaped, ultrashort pulsed laser beam under non-collinear phase-matching configuration. Energy conversion from pump to parametric waves as high as 25 % is obtained owing to the achievement of 1-dimensional spatial-soliton regime, which(More)
Nonlinear losses accompanying self-focusing substantially impact the dynamic balance of diffraction and nonlinearity, permitting the existence of localized and stationary solutions of the 2D + 1 nonlinear Schrödinger equation, which are stable against radial collapse. These are featured by linear, conical tails that continually refill the nonlinear, central(More)
Optical solitons or solitonlike states shed light to blueshifted frequencies through a resonant emission process. We predict a mechanism by which a second propagating mode is generated. This mode, called negative resonant radiation, originates from the coupling of the soliton mode to the negative-frequency branch of the dispersion relation. Measurements in(More)
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(More)
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(More)
We demonstrate the validity of the Shackled-frequency-resolved-optical-gating technique for the complete characterization, both in space and in time, of ultrashort optical pulses that present strong angular dispersion. Combining a simple imaging grating with a Hartmann-Shack sensor and standard frequency-resolved-optical-gating detection at a single spatial(More)