Two-color pump-probe experiments in helium using high-order harmonics
(2003) In European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics 22(1). p.3-11- Abstract
- A pump-probe technique has been applied for measuring the lifetimes and absolute photoionization cross-sections of excited He states. The 1s2p P-1 and 1s3p P-1 states of He are excited by using the 13th and the 14th harmonic, respectively, of a tunable 70 ps dye laser generated in a Kr gas jet. The states are ionized after a varying time delay, by absorption of probe photons with energies between 1.6 and 4.5 eV. Lifetimes of tau(1s2p) = 0.57 ns and tau(1s3p) = 1.76 ns are determined with a precision of about 15%. A significant enhancement of the number of ions present in the lifetime curves at zero time delay for pressures above 6 x 10(-5) mbar is attributed to direct two-photon ionization of He in combination with AC Stark broadening of... (More)
- A pump-probe technique has been applied for measuring the lifetimes and absolute photoionization cross-sections of excited He states. The 1s2p P-1 and 1s3p P-1 states of He are excited by using the 13th and the 14th harmonic, respectively, of a tunable 70 ps dye laser generated in a Kr gas jet. The states are ionized after a varying time delay, by absorption of probe photons with energies between 1.6 and 4.5 eV. Lifetimes of tau(1s2p) = 0.57 ns and tau(1s3p) = 1.76 ns are determined with a precision of about 15%. A significant enhancement of the number of ions present in the lifetime curves at zero time delay for pressures above 6 x 10(-5) mbar is attributed to direct two-photon ionization of He in combination with AC Stark broadening of the excited state and absorption of the XUV light in the medium. Absolute photoionization cross-sections from the He 1s2p P-1 and He 1s3p P-1 states in the threshold region are determined by measuring the saturation of the ionization process with a precision of similar to 25%. In addition, the variation of the relative orientation between the polarization vectors of the pump and probe beams enables the determination of partial photoionization cross-sections. (Less)
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- author
- organization
- publishing date
- 2003
- type
- Contribution to journal
- publication status
- published
- subject
- in
- European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics
- volume
- 22
- issue
- 1
- pages
- 3 - 11
- publisher
- EDP Sciences
- external identifiers
-
- wos:000180850000001
- scopus:0037263791
- ISSN
- 1434-6060
- DOI
- 10.1140/epjd/e2002-00213-1
- language
- English
- LU publication?
- yes
- additional info
- The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Atomic physics (011013005), Physics, Faculty of Technology (011013200)
- id
- be754200-c4d8-4a46-82c8-bf5aa403f02d (old id 318685)
- date added to LUP
- 2016-04-01 15:27:57
- date last changed
- 2022-01-28 05:27:11
@article{be754200-c4d8-4a46-82c8-bf5aa403f02d, abstract = {{A pump-probe technique has been applied for measuring the lifetimes and absolute photoionization cross-sections of excited He states. The 1s2p P-1 and 1s3p P-1 states of He are excited by using the 13th and the 14th harmonic, respectively, of a tunable 70 ps dye laser generated in a Kr gas jet. The states are ionized after a varying time delay, by absorption of probe photons with energies between 1.6 and 4.5 eV. Lifetimes of tau(1s2p) = 0.57 ns and tau(1s3p) = 1.76 ns are determined with a precision of about 15%. A significant enhancement of the number of ions present in the lifetime curves at zero time delay for pressures above 6 x 10(-5) mbar is attributed to direct two-photon ionization of He in combination with AC Stark broadening of the excited state and absorption of the XUV light in the medium. Absolute photoionization cross-sections from the He 1s2p P-1 and He 1s3p P-1 states in the threshold region are determined by measuring the saturation of the ionization process with a precision of similar to 25%. In addition, the variation of the relative orientation between the polarization vectors of the pump and probe beams enables the determination of partial photoionization cross-sections.}}, author = {{Johansson, Allan and Raarup, MK and Li, Zhongshan and Lokhnygin, V and Descamps, D and Lynga, C and Mevel, E and Larsson, Jörgen and Wahlström, Claes-Göran and Aloise, S and Gisselbrecht, M and Meyer, M and L'Huillier, Anne}}, issn = {{1434-6060}}, language = {{eng}}, number = {{1}}, pages = {{3--11}}, publisher = {{EDP Sciences}}, series = {{European Physical Journal D. Atomic, Molecular, Optical and Plasma Physics}}, title = {{Two-color pump-probe experiments in helium using high-order harmonics}}, url = {{https://lup.lub.lu.se/search/files/4398572/2374968.pdf}}, doi = {{10.1140/epjd/e2002-00213-1}}, volume = {{22}}, year = {{2003}}, }