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- Zitnik, M, et al.
(author)
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High resolution multiphoton spectroscopy by a tunable free-electron-laser light.
- 2014
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In: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 113:19
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Journal article (peer-reviewed)abstract
- Seeded free electron lasers theoretically have the intensity, tunability, and resolution required for multiphoton spectroscopy of atomic and molecular species. Using the seeded free electron laser FERMI and a novel detection scheme, we have revealed the two-photon excitation spectra of dipole-forbidden doubly excited states in helium. The spectral profiles of the lowest (-1,0)^{+1} ^{1}S^{e} and (0,1)^{0} ^{1}D^{e} resonances display energy shifts in the meV range that depend on the pulse intensity. The results are explained by an effective two-level model based on calculated Rabi frequencies and decay rates.
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2. |
- Björn, Lars Olof, et al.
(author)
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Technical discussion I - Underwater light measurement and light absorption by algae
- 1996
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In: Scientia Marina. - 0214-8358. ; 60:Suppl.1, s. 293-297
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Journal article (peer-reviewed)abstract
- In this paper concepts and nomenclature of light measurements are discussed. The particular problems of underwater light measurements and the calibration of the equipment were presented. The pros and cons with spectroradiometers and broad band sensors were discussed. The use of specific ultraviolet-B sources for algal photobiology is recommended.
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