Laser-induced orbital projection and diffraction of O- sub(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, Pavicic, D, Meckel, M, Zeidler, D, Pepin, H, Dorner, R, Kieffer, J-C, Villeneuve, D M, Corkum, P B, Staudte, A
• Format: Journal Article
• Language: English
• Published: 07.10.2013
• Subjects: Alignment
• DOI: 10.1080/09500340.2013.771755
• ISSN: 0950-0340

In a velocity map imaging spectrometer, we measured the electron momentum distributions from the ionization of O[Image omitted.] molecules with 800 nm wavelength, 40 fs laser pulses at a peak intensity of [Image omitted.] W cm[Image omitted.]. The molecules were aligned at 0[Image omitted.], 45[Image omitted.] and 90[Image omitted.] 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[Image omitted.], but only partially predicts the decrease in the diffraction signature for smaller alignment angles.