arXiv subjects

Kenichi L. Ishikawa

Publications and source records attributed to Kenichi L. Ishikawa.

56 records · Page 4Linked to original sources

arXiv2009

Intracycle and Intercycle Interferences in Above-Threshold Ionization: the Time Grating

Within a semiclassical description of above-threshold ionization (ATI) we identify the interplay between intracycle and intercycle interferences. The former is imprinted as a modulation envelope on the discrete multiphoton peaks formed by the latter. This allows to unravel the complex interference pattern observed for the full solution of the time-dependent Schrödinger equation (TDSE) in terms of diffraction at a grating in the time domain. These modulations can be clearly seen in the dependence of the ATI spectra on the laser wavelength. Shifts in energy modulation result from the effect of the long Coulomb tail of the atomic potential.

physics.atom-ph↗

arXiv2009

Wavelength dependence of high-order harmonic generation with the ionization and ponderomotive energy controlled by an extreme ultraviolet pulse

We theoretically study the scaling with the driving wavelength of the high-order harmonic generation (HHG) under the simultaneous irradiation of an extreme ultraviolet (XUV) pulse. Surprisingly, when the cutoff energy and ionization yield are fixed, the harmonic yield is nearly independent of the driving wavelength. We identify its origin as the combination of the initial spatial width of the states excited by the XUV pulse, making the wavepacket spreading less prominent, and the shallowing of the ionization potential, which suggests complex nature of the wavelength dependence of HHG.

physics.atom-ph↗