Session 13 – HIGH HARMONIC SPECTROSCOPY

Chair: Eric Mevel, CELIA, Talence, France

  • Olga Smirnova
  • Hyeok Yun
  • Ayelet Julie Uzan
  • Antoine Camper
  • Claude Marceau

#58, 10:30 – 11:00 Time-resolving Attosecond Chiral Dynamics in Molecules with High Harmonic Spectroscopy, R. CIREASA, A.E. BOGUSLAVSKIY, B. PONS, M. C. H. WONG, D. DESCAMPS, S. PETIT, H. RUF, N. THIRE, A. FERRE, J. SUAREZ, J. HIGUET, B. E. SCHMIDT, A.F. ALHARBI, F. LEGARE, V. BLANCHET, B. FABRE, S.PATCHKOVSKII, O. SMIRNOVA, Y. MAIRESSE, AND V. R. BHARDWAJ, We describe high harmonic emission from a random ensemble of chiral molecules in mid-infrared fields. We demonstrate and explain extreme chiral sensitivity of the harmonic response to weakly elliptical fields and use it to time-resolve attosecond chiral dynamics. We predict that driving HHG with tailored circularly or elliptically polarized two-color fields allows one to increase chiral dichroism by orders of magnitude. We also show how the combination of amplitude and phase HHG measurements allows one to detect enantiomeric excess and perform full reconstruction of the time-dependent chiral response.

#59, 11:00 – 11:15 Resolving high-harmonics from multiple orbitals by two-dimensional high-harmonic spectroscopy, HYEOK YUN, KYUNG-MIN LEE, JAE HEE SUNG, KYUNG TAEC KIM, HYUNG TAEK KIM, AND CHANG HEE NAM, High-harmonic radiation from a molecule carries information on electronic structure and dynamics of the molecule. The multiple molecular orbitals contributes to the process of the high harmonic generation. Resolving the contribution of each orbital is crucial for understanding molecular dynamics. We show that two-dimensional highharmonic spectroscopy can resolve high-harmonic radiation emitted from the two highest-occupied molecular orbitals, HOMO and HOMO-1, of aligned molecules. The characteristics attributed to the two orbitals are found to be separately imprinted in odd and even harmonics.

#60, 11:15 – 11:30 Single molecule interferometer via high harmonic generation, A. UZAN, H. SOIFER, O. PEDATZUR, D. AZOURY, M. KRUGER, G. ORENSTEIN, B. BRUNNER, AND NIRIT DUDOVICH, We present a new approach in HHG spectroscopy where the signal is measured in an interferometric manner. Using multicolor fields, we can accurately “shape” the spatio-temporal properties of electron trajectories within the optical cycle. Specifically, we can manipulate the angle of ionization and recollision with attosecond-Angstrom accuracy. When such control is integrated with molecular alignment, we can induce an interferometer at the single-molecule level. In this scheme the arms of the interferometer are represented by different electrons’ trajectories. We show that the interferometric approach molecular orbital, enables a direct reconstruction of the harmonics spectral phase, providing a unique insight into the structure of the molecular orbital.

#61, 11:30 – 11:45 Nitrogen tomographic study with 1.3 μm High Harmonic Generation, S. B. SCHOUN, A. CAMPER, P. AGOSTINI, J. CAILLAT, R. R. LUCCHESE, P. SALIÈRES ,AND L. F. DIMAURO, We measured the amplitude and group delay of High Harmonics generated in nitrogen with 1.3 micron laser pulses up to 70 eV for several angles between the driving field polarization and the molecular ensemble axis of symmetry. We compare our results with an angle-averaged photoionization scattering-wave dipole. We find quantitative agreement above 30 eV and qualitative agreement over the whole spectrum. Thanks to the broader spectral range and finer sampling achieved at long wavelengths, our study emphasizes features previously undetected by High Harmonic Spectroscopy and shines a new light on the tomography of molecular orbitals using this technique.

#62, 11:45 – 12:00 Photoelectron spectroscopy of molecular nitrogen using high order harmonics of 800 nm and of 400 nm femtosecond laser pulses, CLAUDE MARCEAU, T.J. HAMMOND, GRAHAM G. BROWN, PAUL B. CORKUM, AND DAVID M. VILLENEUVE, We discuss the advantages of using an ultraviolet laser as a source for high harmonic generation based photoelectron spectroscopy. With a 400 nm pump source, we can resolve vibrational lines of three different final electronic state of the N2 + ion.