Transcript Document
Scope 1. Ionization of molecules - ( MO-ADK theory) • Alignment dependence – imaging MO’s (KSU data) (Experiments: double ionization; high-harmonic generation) • “Molecular clock”: Time is read from the kinetic energy release of the fragments with sub-fs accuracy • Attosecond XUV + IR laser physics • how to extract lifetime of autoionizing states • Stark effect of laser-assisted photoexcitations • Probing electron dynamics in the time domain 3. Summary APT-attosecond pulse train issues 130 as from the plateau region– the harmonics must be phase locked two sources of asynchronism: 1.short and long paths, thus two bursts– select short by phase matching condition by focusing before the gas jet and a diaphram after 2.different harmonics, due to different recombination times, linear chirp, limits the as pulse durations to about 100as, need chirp compensation Relative phases measured by two-photon, two color ionizations— sideband analysis--RABITT other works– trying to relate the harmonics to electron dynamics HHG facts: plateau region has positive chirp for the short trajectory phase locked in the cutoff region z: off the focus presented by the Saclay group see Mairesse et al PRL 93, 163901(04); also Science 302, 1540 (03) The Milano group also made such studies using short pulses with CEP stabilized not cep sensitive from simulation, PRL92,113904(04) apt with 170as at Lund --simulation From RABITT amplitude shaping phase shaping APT pulses APT+IR good HHG sharp harmonics selecting the time of ionization by apt schaffer et al PRL92, 023003(04) preliminary data from U. Keller’s group confirm the HHG enhancement Lund’s group measured the ATI enhancement to higher electron energies HHG as light sources • Crete’ group, use 7th and 13th harmonics for cross correlation experiments Attosecond electron bursts for imaging –”industry?” • Corkum• Paulus– use the phase information in the tunneling electrons for interference? • M. Lezius• Ivanov– theory for imaging by electrons (quite complicated, but not impossible) • Villeneuve– imaging thru HHG (N2 Nature04) • Kietzer-ALLE need to know e-wave packet better. Krausz’s recent work • tried IR-pump/XUV probe– signal too weak • XUV pump/IR probe look at the time of shakeup electrons, rise time is about 4fs The COLTRIMS people • Doerner- e-e spectra, sequential, nonsequential, also circularly polarized, laser lab soon • Moshammer– double and multiple ionization cold recoil ions • Helm- negative ions, atoms All good talks– theory done by experimentalists mostly, S-matrix theory does not really work HHG of molecules • Marangnos+Italy group • alignment dependence, short and long pulses; difference in H2 and D2 Activities-Colloquium at Univ. of Electrocommunications Seminar at RIKEN 1st talk at the conference (more mixed audience) covered: alignment-depn ionization rates and imaging of the electron cloud molecular cloud laser-assisted autoionization Intense XUV and soft X-ray source Soft X-ray 0.33 J @ = 29.6 nm (Ti:Sapphire H27) focused to an area of 10m2 by a mirror Assuming the pulse duration < 30 fs 1014 W/cm2 Mashiko et al., Opt. Lett. 29, 1927 (2004) • Above-threshold ionization (ATI) of He – Sekikawa et al., Nature 432, 605 (2004) XUV – h = 27.9 eV • ATI & Two-photon double ionization (TPDI) of He Soft X-ray – Hasegawa et al., Phys. Rev. A, in press; Nabekawa et al., Phys. Rev. Lett., in press – h = 41.8 eV High-order harmonic generation (HHG) • • RIKEN, Laser Technology Laboratory (K. Midorikawa) Takahashi et al. – 25 nJ @ = 13.5 nm (Ti:S H59) – 0.33 J Opt. Lett. 27, 1920(2002) JOSA B 20, 158 (2003) @ = 29.6 nm (Ti:S H27) @ = 54 nm (Ti:S H15) – 1 J – 4.7 J @ = 62.3 nm (Ti:S H13) – 7 J @ = 72.7 nm (Ti:S H11) Appl. Phys. Lett. 84, 4 (2004) Hergott et al. Phys. Rev. A 66, 021801 (2002) CEA-Saclay, DSM/DRECAM/SPAM (P. Salieres) – • Phys. Rev. A 66, 021802(2002) 1.9 J @ = 53.3 nm (Ti:S H15) University of Tokyo, ISSP (S. Watanabe) – Yoshitomi et al. Opt, Lett. 27, 2170 (2002) 1.2 J @ = 49.7 nm (KrF Excimer H5)