Excitation of ultrashort bursts of harmonics of the radiation during ionization of a gas by an intense light pulse
Vanin E. V. , Kim A. V. , Sergeev A. M. , Downer M. C.
A self-consistent model for a nonlinear interaction of an intense femtosecond-range light pulse with a gas of quantum particles (atoms) is discussed. During fast multiphoton ionization of the gas, the spectral lines of harmonics of the radiation undergo a substantial broadening and a blue shift. A pulse of the third harmonic with a duration equal to less than three periods of the exciting optical field can be generated at an efficiency ~10% in terms of the field amplitude.