title: Vacuum-ultraviolet frequency-modulation spectroscopy.
abstract: Frequency-modulation (FM) spectroscopy has been extended to the vacuum-ultraviolet (VUV) range of the electromagnetic spectrum. Coherent VUV laser radiation is produced by resonance-enhanced sum-frequency mixing (νVUV=2νUV+ν2) in Kr and Xe using two near-Fourier-transform-limited laser pulses of frequencies νUVand ν2. Sidebands generated in the output of the second laser (ν2) using an electro-optical modulator operating at the frequency νmodare directly transferred to the VUV and used to record FM spectra. Demodulation is demonstrated both at νmodand 2νmod. The main advantages of the method compared to VUV absorption spectroscopy are its background-free nature, the fact is that its implementation using table-top laser equipment is straightforward and that it can be used to record VUV absorption spectra of cold samples in skimmed supersonic beams simultaneously with laser-induced-fluorescence and photoionization spectra. To illustrate these advantages, we present VUV FM spectra of Ar, Kr, and N2in selected regions between 105000 cm-1and 122000 cm-1.
authors.affiliation: Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: U
authors.initials: U
authors.lastname: Hollenstein
authors.affiliation: Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: H
authors.initials: H
authors.lastname: Schmutz
authors.affiliation: Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: J A
authors.initials: JA
authors.lastname: Agner
authors.affiliation: Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Sommavilla
authors.affiliation: Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland.
authors.forename: F
authors.initials: F
authors.lastname: Merkt