Wavelength scaling of high-harmonic yield: Threshold phenomena and bound state symmetry dependence

Describing harmonic generation (HG) in terms of a system's complex quasienergy, the harmonic power P-Delta E(lambda) (over a fixed interval, Delta E, of harmonic energies) is shown to reproduce the wavelength scaling predicted recently by two groups of authors based on solutions of the time-dependent Schrodinger equation: P-Delta E(lambda)similar to lambda(-x), where x approximate to 5-6. Oscillations of P-Delta E(lambda) on a fine lambda scale are then shown to have a quantum origin, involving threshold phenomena within a system of interacting ionization and HG channels, and to be sensitive to the bound state wave function's symmetry.