Quasienergy spectrum of complex atoms

Abstract

Representative sections of the quasienergy spectrum of argon and of alkali-metal atoms are presented for wavelengths between $250\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ and $800\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ and excursion amplitudes up to ${\ensuremath{\alpha}}_{0}=20\phantom{\rule{0.3em}{0ex}}\text{a.}\mathrm{u}$. The variation of the quasienergy spectrum with the wavelength of the laser field is discussed. It is shown that large-scale changes in its topology arise from laser-induced degeneracies with states without physical high-intensity or low-intensity limits.