We present the results of experimental and theoretical studies of high-order harmonic generation (HHG) in plasmas containing fullerenes using pulses of different duration and wavelength. We find that the harmonic cutoff is extended in the case of few-cycle pulses (3.5 fs, 29th harmonic) compared to longer laser pulses (40 fs, 25th harmonic) at the same intensity. Our studies also include HHG in fullerenes using 1300 and 780 nm multicycle (35 and 40 fs) pulses. For 1300 nm pulses, an extension of the harmonic cutoff to the 41st order was obtained, with a decrease in conversion efficiency that is consistent with theoretical predictions based on wave packet spreading for single atoms. Theoretical calculations of fullerene harmonic spectra using the single active electron approximation were carried out for both few-cycle and multicycle pulses.
© 2012 Optical Society of America
Original Manuscript: August 10, 2012
Revised Manuscript: October 23, 2012
Manuscript Accepted: October 23, 2012
Published: December 3, 2012
Rashid A. Ganeev, Christopher Hutchison, Tobias Witting, Felix Frank, Sébastien Weber, William A. Okell, Emilio Fiordilino, Dario Cricchio, Franco Persico, Amelle Zaïr, John W. G. Tisch, and Jonathan P. Marangos, "High-order harmonic generation in fullerenes using few- and multi-cycle pulses of different wavelengths," J. Opt. Soc. Am. B 30, 7-12 (2013)