V. Petrillo

Apparent superluminal advancement of a single photon far beyond its coherence length

We present experimental results relative to superluminal propagation based on a single photon traversing an optical system, called a 4f-system, which acts singularly on the photons spectral component phases. A single photon is created by a continuous wave (CW) laser light down-conversion process. The introduction of a linear spectral phase function will lead to the shift of the photon peak far beyond the coherence length of the photon itself (an apparent superluminal propagation of the photon). Superluminal group velocity detection is done by interferometric measurement of the temporally shifted photon with its correlated untouched reference. The observed superluminal photon propagation complies with causality. The operation of the optical system allows the origin of the apparent superluminal photon velocity to be elucidated. The experiment foresees a superluminal effect with single-photon wavepackets.

Seeded FEL with two energy level electron beam distribution at SPARC_LAB

We present the experimental evidence of the generation of coherent and statistically stable Free-Electron Laser (FEL) two color radiation obtained by seeding an electron double peaked beam in time and energy with a single peaked laser pulse. The FEL radiation presents two neat spectral lines, with time delay, frequency separation and relative intensity that can be accurately controlled. The analysis of the emission shows a temporal coherence and regularity in frequency significantly enhanced with respect to the Self Amplified Spontaneous Emission (SASE).

Dual color x-rays from Thomson or Compton sources

We analyze the possibility of producing two color X or γ radiation by Thomson/Compton back-scattering between a high intensity laser pulse and a two-energy level electron beam, constituted by a couple of beamlets separated in time and/or energy obtained by a photoinjector with comb laser techniques and linac velocity bunching. The parameters of the Thomson source at SPARC_LAB have been simulated, proposing a set of values for a realistic experiments.

Novel types of ionizing radiation sources at LNF-PLASMONX facility

The INFN Strategic Project PLASMONX (PLASma acceleration and MONochromatic X-ray production) deals with the creation of a High Intensity Laser Laboratory at LNF (HILL@LNF) beside the SPARC bunker, with which it will communicate via a channel for the propagation of laser beams. In this laboratory FLAME ( Frascati Laser for Acceleration and Multidisciplinary Experiments), a 200TW, 30fs, 10Hz Ti:Sapphire Laser, will be set up. The main goals of this project are: 1) demonstration of high-gradient acceleration of relativistic electrons injected into electron plasma waves excited by ultra-short, super-intense laser pulses; 2) development of a monochromatic and tuneable X-ray source in the 20-1000 keV range, based on Thomson Scattering of laser pulses by the 20-200 MeV electrons of the LINAC of the SPARC project. One of the aims of the project consists in the realization of a pulsed source of ionizing radiation for R&D activity in different fields.

Dynamics of two quantum entangled particles interacting with a potential barrier in an EPR experiment

The effect of a position measurement on one component of a two-particle wave packet in a regularized space-momentum entangled state is analyzed. The wave packet interacts in the physical space with a potential barrier. When a position or momentum measurement is performed on one particle, a consequent strong modification of the dynamics of the other particle occurs.

SPARC/X projects

SPARC and SPARX are two different initiatives toward an X-ray FEL SASE source at LNF. SPARC is a high gain FEL project devoted to provide a source of visible and VUV radiation while exploiting SASE mechanism. An advanced Photo-Injector system, emittance self-compensating RF-gun plus a 150 MeV Linac, will inject a high quality e-beam into the undulator to generate high brilliance FEL radiation in the visible region at the fundamental wavelength, (530 nm). The production of flat top drive laser beams, high peak current bunches, and an emittance compensation scheme will be investigated together with the generation of higher harmonic radiation in the VUV region. SPARX is the direct evolution of such a high gain SASE FEL towards the 13.5 and 1.5 nm operating wavelengths, at 2.5 GeV. The first phase of the SPARX project, fiinded by Government Agencies, will be focused on R&D activity on critical components and techniques for future X-ray facilities as described in this paper.