Dresden 2011 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 7: Poster I

A 7.12: Poster

Montag, 14. März 2011, 16:00–18:30, P1

High-Order Harmonic Generation in the Presence of a Resonance — •Maria Tudorovskaya^1,2 and Manfred Lein¹ — ¹Leibniz Universitaet Hannover, Hannover, Germany — ²Institut fuer Physik, Universitaet Kassel, Kassel, Germany

High-order harmonic generation is a nonlinear process occuring in the intense laser field affecting on atomic or molecular targets. We investigate high-order harmonic generation from laser-irradiated atoms with a potential that supports a shape resonance. Although the process leads to emittion of photons with very high energy, its effitiency is not very high. Certain harmonics is enhanced due to the presence of the resonance. From the numerical solution of the time-dependent Schroedinger equation, we calculate the harmonic spectra and make time-frequency analysis, revealing the separate contribution of the short and long trajectories as well as the resonance. Using potentials with different shape, we show how parameters of the potential barrier can affect the resonance in the spectrum. We show that significant resonance in the spectrum can be achieved from the pulse length being equal to just a few optical periods of the laser. We simulate the phase matching in a gas medium by coherent summation over intensities. It is shown that the contribution of the long trajectories becomes negligible, but the signature of the resonance is still significant.