Phase-matching analysis of high-order harmonics generated by truncated Bessel beams in the sub-10-fs regime

Journal Article · Mon Sep 01 00:00:00 EDT 2003 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.68.033806· OSTI ID:20640232

Altucci, C ^[1]; Bruzzese, R; De Lisio, C ^[1]; Nisoli, M; Priori, E; Stagira, S ^[2]; Pascolini, M; Poletto, L; Villoresi, P ^[3]; Tosa, V ^[4]; Midorikawa, K ^[4]

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1. Coherentia-INFM UdR di Napoli and Universita 'Federico II', Dipartimento di Scienze Fisiche-Complesso di Monte S. Angelo, via Cintia, 80126 Naples (Italy)
2. Ultras-INFM UdR di Milano, Dipartimento di Fisica, Politecnico di Milano, Milan (Italy)
3. Laboratory for Ultraviolet and X-ray Optical Research-INFM DEI-Universita di Padova, Padova (Italy)
4. Laser Technology Laboratory, RIKEN (Japan)

We describe a very simple physical model that allows the analysis of high-order harmonic generation in gases when the pumping laser beam has an intensity profile that is not Gaussian but truncated Bessel. This is the typical experimental condition when sub-10-fs pump-laser pulses, generated by the hollow fiber compression technique, are used. This model is based on the analysis of the phase-matching conditions for the harmonic generation process revisited in view of the new spatial mode of the fundamental beam. In particular, the role of the atomic dipole phase and the geometric phase terms are evidenced both for harmonics generated in the plateau and in the cutoff spectral regions. The influence of dispersion introduced by free electrons produced by laser ionization has also been discussed in some detail. Spatial patterns of far-field harmonics are then obtained by means of a simplified algorithm which allows one to avoid the numerical integration of the harmonic beam propagation equation. Experimental spatial distributions and divergence angles of high-order harmonics generated in Ne with 7-fs titanium-sapphire pulses are compared with numerical simulations in various experimental conditions. The agreement between measurements and calculated results is found to be very satisfactory.

• OSTI ID: 20640232
• Journal Information: Physical Review. A, Vol. 68, Issue 3; Other Information: DOI: 10.1103/PhysRevA.68.033806; (c) 2003 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ALGORITHMS
COMPUTERIZED SIMULATION
DIPOLES
ELECTRONS
FIBERS
GASES
HARMONIC GENERATION
HARMONICS
LASER RADIATION
OPTICAL PUMPING
PHOTOIONIZATION
PULSES
SPATIAL DISTRIBUTION