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ABSTRACT: The spatiotemporal effects generated in the wake of a laser filament propagating in nitrogen are investigated. At suitable time delays, a probe light pulse propagating along the wake experiences a strong spatial confinement and a noticeable spectral broadening at the same time. Numerical simulations, well reproducing the experimental findings, show the key role of the impulsive rotational Raman response in the observed phenomena.
Physical Review Letters 03/2008; 100(12):123006. · 7.37 Impact Factor
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ABSTRACT: Ultrabroadband self-phase-stabilized near-IR pulses have been generated by difference-frequency generation of a filament broadened supercontinuum followed by two-stage optical parametric amplification. Pulses with energy up to 1.2 mJ and duration down to 17 fs are demonstrated. These characteristics make such a source suited as a driver for high-order harmonic generation and isolated attosecond pulse production.
Optics Letters 11/2007; 32(20):2957-9. · 3.40 Impact Factor
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F Calegari,
G Valentini,
C Vozzi,
E Benedetti,
J Cabanillas-Gonzalez,
A Faenov, S Gasilov,
T Pikuz,
L Poletto,
G Sansone,
P Villoresi,
M Nisoli,
S De Silvestri,
S Stagira
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ABSTRACT: Elemental sensitivity in soft x-ray imaging of thin foils with known thickness is observed using an ultrafast laser-plasma source and a LiF crystal as detector. Measurements are well reproduced by a simple theoretical model. This technique can be exploited for high spatial resolution, wide field of view imaging in the soft x-ray region, and it is suitable for the characterization of thin objects with thicknesses ranging from hundreds down to tens of nanometers.
Optics Letters 10/2007; 32(17):2593-5. · 3.40 Impact Factor
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ABSTRACT: Summary form only given. In this paper, a scheme for the generation of high-energy, few-optical-cycle, carrier-envelope-phase (CEP) stabilized pulses in the IR around 1.5 mum is realised. The system is driven by a CPA Ti:sapphire laser (50 fs, 120 mJ, 800 nm, 10 Hz). A 0.6-mJ pulse is spectrally broadened by filamentation in a gas cell filled with krypton and compressed by chirped mirrors down to 10 fs. A high-energy passively CEP-stabilized seed is then produced by intra-pulse difference frequency (DF) generation seeded by the broadband continuum of the filament. This seed is then boosted in energy by an optical parametric amplifier (OPA) producing CEP-stabilized pulses with 15-muJ energy. The development of a second high-energy broadband OPA stage will obtain mJ-level few-cycle passively CEP-stabilized IR pulses that will be ideal driver for high order harmonic generation toward the soft-X region and for attosecond pulse generation.
Lasers and Electro-Optics, 2007 and the International Quantum Electronics Conference. CLEOE-IQEC 2007. European Conference on; 07/2007
