Efficient third-harmonic generation through tailored IR femtosecond laser pulse filamentation in air.

Institute of Electronic Structure and Laser, Foundation for Research and Technology Hellas, P.O. Box 1527, 71110, Heraklion, Greece.
Optics Express (Impact Factor: 3.55). 04/2009; 17(5):3190-5. DOI: 10.1364/OE.17.003190
Source: PubMed

ABSTRACT The process of third-harmonic generation during the filamentation of intense IR femtosecond laser pulses in air is investigated experimentally. It is shown that the introduction of a thin plasma string created by another femtosecond pulse, perpendicularly to the filament's path, dramatically reshapes the third-harmonic beam into a Bessel-like far-field distribution, while at the same time significantly enhances, up to 250 times, its conversion efficiency.

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