Y Mairesse et al 2008 New J. Phys. 10 025015 doi:10.1088/1367-2630/10/2/025015
Electron wavepacket control with elliptically polarized laser light in high harmonic generation from aligned molecules
Focus on Attosecond PhysicsY Mairesse1,2,5, N Dudovich1,3, J Levesque1,4, M Yu Ivanov1, P B Corkum1 and D M Villeneuve1
Show affiliationsPart of Focus on Attosecond Physics
We study experimentally and theoretically the high harmonic emission from aligned samples of nitrogen and carbon dioxide, in an elliptically polarized laser field. The ellipticity induces a lateral shift of the recombining electron wavepacket in the generation process. We show that this effect, which is well known from high harmonic generation (HHG) in atoms, can be useful to maintain the plane wave approximation in the case of HHG from molecules whose orbitals contain nodal planes. The study of the harmonic signal as a function of molecular alignment also reveals the role of the ellipticity on the recollision angle of the electron wavepacket, which can be used to accurately track the position of resonances in harmonic spectra.
-
GENERAL SCIENTIFIC SUMMARY
Introduction and background. When an atom or molecule is exposed to an intense femtosecond laser pulse, the electric field of the laser is stronger than the binding potential which holds electrons to the atoms. Once it is free of the atomic potential, the electron is at the mercy of the laser field. The field pulls the electron far from the ion, then drives it back within the optical period of the laser, a few femtoseconds. Although it is improbable, the electron can recombine with the parent ion, and will give up its kinetic energy in the form of a photon in the soft x-ray portion of the spectrum. This process is called high harmonic generation, and results in a coherent beam of photons consisting of one or more attosecond-duration pulses. The recombination process is a quantum transition between a continuum state (the free electron) and the bound state, and so it contains information about the bound state wave function. It has been shown that the high harmonic spectrum from molecules which are aligned in space can be used to form an image of a single molecular orbital wave function.Main results. The main difficulty in using high harmonic emission to measure orbital wave functions is that the orbitals of most molecules have nodal planes in which the wave function is zero. Since the continuum wave function is derived from the bound state orbital, it too will have nodes for certain molecular angles. To get around this problem, we used elliptically polarized laser light to push the continuum wave function laterally, thereby pushing the nodal plane away from the molecule.
Wider implications. Since the continuum wave function can be manipulated by the laser field, it is possible to decouple the ionization and recombination processes. This approach can be generalized to other means of modifying the laser electric field on a sub-cycle time scale. For example, the combination of a laser field with its second harmonic at an orthogonal polarization allows the recolliding electron to be directed into the side of the molecule, giving another view of the orbital wave function.
- PACS
- Subjects
- Dates
-
Issue 2 (February 2008)
Received 22 September 2007
Published 29 February 2008
-
Electron wavepacket control with elliptically polarized laser light in high harmonic generation from aligned molecules
Y Mairesse et al 2008 New J. Phys. 10 025015
-
Adaptive chemistry computations of reacting flow
J M Ortega et al 2007 J. Phys.: Conf. Ser. 78 012054
-
Final report on COOMET Rockwell PTB/KazInMetr comparison
K Herrmann and M Zhamanbalin 2009 Metrologia 46 07001
-
An optimized kHz two-colour high harmonic source for seeding free-electron lasers and plasma-based soft x-ray lasers
G Lambert et al 2009 New J. Phys. 11 083033
-
Comments on two-loop four-particle amplitude in superstring theory
Wu-Jun Bao and Chuan-Jie Zhu JHEP05(2003)056
-
Carving fiber-top cantilevers with femtosecond laser micromachining
A A Said et al 2008 J. Micromech. Microeng. 18 035005
-
A geometric theory of swimming: Purcell's swimmer and its symmetrized cousin
J E Avron and O Raz 2008 New J. Phys. 10 063016
-
Exact Floquet states of a driven condensate and their stabilities
Wenhua Hai et al 2008 J. Phys. B: At. Mol. Opt. Phys. 41 095301
-
Dynamical compactification from de Sitter space
Sean M. Carroll et al JHEP11(2009)094
-
Nonuniform shrinkage and stretching of polymerized nanostructures fabricated by two-photon photopolymerization
Yan Li et al 2008 Nanotechnology 19 055303
Users also read
What's this?- Resonant and rolling droplet
- Generation of a large amount of energetic electrons in complex-structure bubble
- Huge electrocaloric effect in Langmuir–Blodgett ferroelectric polymer thin films