Laser-induced orbital projection and diffraction of O-2 with velocity map imaging

• Published in: Journal of modern optics Vol. 60; no. 17; pp. 1395 - 1408
• Main Authors: Comtois, D., Bandulet, H.-C., Spanner, M., Pavičić, D., Meckel, M., Zeidler, D., Pépin, H., Dörner, R., Kieffer, J.-C., Villeneuve, D.M., Corkum, P.B., Staudte, A.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 07.10.2013
• Subjects: laser induced electron diffraction; orbital imaging; velocity map imaging
• ISSN: 0950-0340; 1362-3044
• DOI: 10.1080/09500340.2013.771755

In a velocity map imaging spectrometer, we measured the electron momentum distributions from the ionization of O molecules with 800 nm wavelength, 40 fs laser pulses at a peak intensity of  W cm . The molecules were aligned at 0 , 45 and 90 relative to the laser polarization prior to ionization. We show that for all alignments the low momentum region - populated by direct electrons which do not recollide with the parent ion - is consistent with the ionized orbital being filtered and projected onto the continuum electron wave packet. In the high momentum region - populated by rescattered electrons - we observe that the pattern created by diffraction of the recolliding wave packet by the ion core disappears as the alignment gets closer to the laser field axis. We find that a two-slit diffraction model agrees well with the results for molecules aligned at 90 , but only partially predicts the decrease in the diffraction signature for smaller alignment angles.