Electron trajectory selection for high harmonic generation inside a short hollow fiber

Igarashi, Hajime; Makida, Ayumu; Sekikawa, Taro

doi:10.1364/oe.21.020632

Cited by 6 publications

(7 citation statements)

References 23 publications

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“…Aer the second harmonic (¼3.1 eV) generation by a LiB 3 O 5 (LBO) crystal (500 mm thickness) for the pump pulses with a pulse energy of 40 mJ, the remaining fundamental pulses were focused into a Kr pulse gas jet for high harmonic generation. The 19th harmonic (¼29.5 eV) for the probe was selected among many harmonics by a time-delay compensated monochromator (TDCM), [33][34][35][36][37] enabling the single harmonic selection with the time duration preserved. A TDCM consists of a pair of toroidal gratings and a slit: the rst grating and a slit select the harmonic order and the second grating compensates for the pulse front tilt caused by the diffraction on the rst grating.…”

Section: Methodsmentioning

confidence: 99%

Structural dynamics of photochemical reactions probed by time-resolved photoelectron spectroscopy using high harmonic pulses

et al. 2016

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Femtosecond ring-opening dynamics of 1,3-cyclohexadiene (CHD) in gas phase upon two-photon excitation at 400 nm (=3.1 eV) was investigated by time-resolved photoelectron spectroscopy using 42 nm (=29.5 eV) high harmonic photons probing the dynamics of the lower-lying occupied molecular orbitals (MOs), which are the fingerprints of the molecular structure. After 500 fs, the photoelectron intensity of the MO constituting the C[double bond, length as m-dash]C sigma bond (σ) of CHD was enhanced, while that of the MO forming the C-C sigma bond (σ) of CHD was decreased. The changes in the photoelectron spectra suggest that the ring of CHD opens to form a 1,3,5-hexatriene (HT) after 500 fs. The dynamics of the σ and σ bands between 200 and 500 fs reflects the ring deformation to a conical intersection between the 2A and 1A potential energy surfaces prior to the ring-opening reaction.

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Section: Methodsmentioning

confidence: 99%

Structural dynamics of photochemical reactions probed by time-resolved photoelectron spectroscopy using high harmonic pulses

et al. 2016

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“…Finally, we would like to emphasize that the complete separation of a single high harmonic order from the others by a time-delay compensated monochromator (TDCM) − enabled us to observe MOs with an ionization energy that is larger by 6 eV than HOMO. The observation over a large spectral region makes it possible to detect the deformation of the molecular structure upon photoexcitation.…”

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confidence: 99%

Ultrafast Relaxation Dynamics in trans-1,3-Butadiene Studied by Time-Resolved Photoelectron Spectroscopy with High Harmonic Pulses

Makida

Igarashi

Fujiwara

et al. 2014

J. Phys. Chem. Lett.

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In trans-1,3-butadiene, the ultrafast relaxation from the doubly excited state 2(1)Ag and the corresponding recovery of the ground state 1(1)Ag were observed simultaneously for the first time by time-resolved photoelectron spectroscopy (TRPES) using 29.5 eV high harmonic pulses. The fast recovery of 1(1)Ag shows that the following dissociation upon photoexcitation takes place after returning to the ground state. At 427 fs after photoexcitation, only the ionization energy from the C═C σ bond was found to remain shifted. Accompanying theoretical calculations with an assumption of Koopmans' theorem show that the ionization energy of the C═C σ bond is modulated by vibrational excitation of the antisymmetric C═C stretching mode. TRPES by high harmonics can probe the changes in the molecular structure sensitively.

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“…The geometric phase of the laser beam does not vary with the radial distance. Harmonic generation experiments in a waveguide have been widely used464748 to create quasi-phase matching (QPM) conditions4950, to generate soft X-ray high harmonics5152 or keV-harmonics with mid-infrared lasers405354.…”

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Optimal generation of spatially coherent soft X-ray isolated attosecond pulses in a gas-filled waveguide using two-color synthesized laser pulses

Jin

Hong

Lin

2016

Sci Rep

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We numerically demonstrate the generation of intense, low-divergence soft X-ray isolated attosecond pulses in a gas-filled hollow waveguide using synthesized few-cycle two-color laser waveforms. The waveform is a superposition of a fundamental and its second harmonic optimized such that highest harmonic yields are emitted from each atom. We then optimize the gas pressure and the length and radius of the waveguide such that bright coherent high-order harmonics with angular divergence smaller than 1 mrad are generated, for photon energy from the extreme ultraviolet to soft X-rays. By selecting a proper spectral range enhanced isolated attosecond pulses are generated. We study how dynamic phase matching caused by the interplay among waveguide mode, neutral atomic dispersion, and plasma effect is achieved at the optimal macroscopic conditions, by performing time-frequency analysis and by analyzing the evolution of the driving laser’s electric field during the propagation. Our results, when combined with the on-going push of high-repetition-rate lasers (sub- to few MHz’s) may eventually lead to the generation of high-flux, low-divergence soft X-ray tabletop isolated attosecond pulses for applications.

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Electron trajectory selection for high harmonic generation inside a short hollow fiber

Cited by 6 publications

References 23 publications

Structural dynamics of photochemical reactions probed by time-resolved photoelectron spectroscopy using high harmonic pulses

Structural dynamics of photochemical reactions probed by time-resolved photoelectron spectroscopy using high harmonic pulses

Ultrafast Relaxation Dynamics in trans-1,3-Butadiene Studied by Time-Resolved Photoelectron Spectroscopy with High Harmonic Pulses

Optimal generation of spatially coherent soft X-ray isolated attosecond pulses in a gas-filled waveguide using two-color synthesized laser pulses

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