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A: Atomphysik

A 3: Multi Photon Processes

A 3.6: Vortrag

Montag, 2. April 2001, 17:00–17:15, H1058

Numerical ab initio studies of harmonic generation from ring-shaped molecules in laser fields — •F. Ceccherini and D. Bauer — Theoretical Quantum Electronics, Darmstadt University of Technology, Hochschulstr. 4a, 64289 Darmstadt

When a laser pulse impinges on a molecule which is invariant under certain symmetry operations selection rules for harmonic generation (HG) arise. In the case of a molecule with N-fold discrete rotational symmetry (with respect to the laser pulse propagation direction) which is placed in circularly polarized laser light of frequency ω₁ the selection rules allow only those harmonics with frequency (k N± 1)ω₁, k=1,2,3,.… [1]. For a short wavelength source it is desirable to have either k or N as big as possible.

We study numerically HG from two-dimensional, ring-shaped model molecules in laser fields. Those models can be thought to mimic ring-like aromatic compounds like benzene, or even nanotubes. Harmonic yields and their dependence on laser frequency and intensity are presented. Similarities and differences with respect to a simpler, effectively one-dimensional model [2] are discussed.

[1] Ofir E. Alon, Vitali Averbukh, and Nimrod Moiseyev, Phys. Rev. Lett. 80, 3743 (1998). [2] D. Bauer and F. Ceccherini, to appear in Laser & Particle Beams.