High-harmonic generation and periodic level crossings: time profile and control

C. Figueira de Morisson Faria; I Rotter

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arXiv · physics/0112076

High-harmonic generation and periodic level crossings: time profile and control

C. Figueira de Morisson Faria·I Rotter

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Abstract

We investigate high-harmonic generation in closed systems, using the two-level atom as a simplified model. By means of a windowed Fourier transform of the time-dependent dipole acceleration, we extract the main contributions to this process within a cycle of the driving field. We show that the patterns obtained can be understood by establishing a parallel between the two-level atom and the three-step model. In both models, high-harmonic generation is a consequence of a three-step process, which involves either the continuum and the ground state, or the adiabatic states of the two-level Hamiltonian. The knowledge of this physical mechanism allows us to manipulate the adiabatic states, and consequently the harmonic spectra, by means of a bichromatic driving field. Furthermore, using scaling laws, we establish sharp criteria for the invariance of the physical quantities involved. Consequently, our results can be extended to a broader parameter range, as for instance those characteristic of solid-state systems in strong fields.

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C. Figueira de Morisson Faria, I Rotter. 2001-12-21. High-harmonic generation and periodic level crossings: time profile and control. https://arxiv.org/abs/physics/0112076

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