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 PΔE(λ) (over a fixed interval, ΔE, of harmonic energies) is shown to reproduce the wavelength scaling predicted recently by two groups of authors based on solutions of the time-dependent Schrödinger equation: PΔE(λ) ~ λ–x, where x ≈ 5–6. Oscillations of PΔE(λ) on a fine λ 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