Generation of vacuum-ultraviolet radiation in H sub 2 by nonlinear optical processes near the EF - and B -state resonances

Journal Article · Sun Dec 01 00:00:00 EST 1991 · Physical Review A. General Physics; (United States)

DOI:https://doi.org/10.1103/PhysRevA.44.7530· OSTI ID:5505190

Czarnetzki, U; Doebele, H F ^[1]

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1. Institut fuer Laser-und Plasmaphysik, Universitaet Gesamthochschule Essen, D-4300 Essen 1 (Germany)

We report on the observation of several nonlinear optical processes in connection with two-photon excitation of H{sub 2} by 193-nm radiation generated by a narrow-bandwidth ArF laser system: stimulated electronic hyper-Raman scattering, parametric four-wave mixing (PFWM), and stimulated resonant Raman scattering (SRRS). These processes lead to the generation of several intense lines in the ir and vacuum ultraviolet (vuv). vuv generation occurs by two interconnected schemes: first, a vuv wave at {lambda}{similar to}109 nm is generated by PFWM (power up to 16 kW). This wave subsequently generates Stokes lines around {lambda}{similar to}150 nm by SRRS. The frequencies of these waves are tunable over spectral intervals of {similar to}20 cm{sup {minus}1} by phase matching with admixture of various gases (e.g., noble gases, N{sub 2}, D{sub 2}). With additional irradiation of ir laser radiation, four-wave mixing (FWM) takes place. In this case, continuously tunable vuv radiation (tuning range {similar to}600 cm{sup {minus}1}) can be generated with power in the 10- and 100-kW range. The tuning ranges are localized around the rovibronic resonances {ital X}-{ital B}. FWM is not possible on resonance. As in the case of PFWM, Stokes lines are generated by SRRS, tunable over intervals up to {similar to}60 cm{sup {minus}1}. The susceptibilities governing the processes involved are calculated. The agreement between the theoretical expectations and the experimental results is very good with respect to the frequency dependence. The calculated absolute values of the vuv intensities, however, turn out to be by far too high. This is due to the neglect of several limiting processes which will be discussed together with the experimental results. In addition to the processes mentioned above, several {ital B}-{ital X} resonance transitions exhibit a limited tunability ({similar to}10 cm{sup {minus}1}).

• OSTI ID: 5505190
• Journal Information: Physical Review A. General Physics; (United States), Vol. 44:11; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
HYDROGEN
EXTREME ULTRAVIOLET SPECTRA
EMISSION SPECTRA
ENERGY-LEVEL TRANSITIONS
EXCIMER LASERS
EXCITATION
FREQUENCY MIXING
NONLINEAR OPTICS
PHOTON-MOLECULE COLLISIONS
RADIATIVE DECAY
RESONANCE
COLLISIONS
DECAY
ELEMENTS
GAS LASERS
LASERS
MOLECULE COLLISIONS
NONMETALS
OPTICS
PARTICLE DECAY
PHOTON COLLISIONS
SPECTRA
ULTRAVIOLET SPECTRA
664300* - Atomic & Molecular Physics- Collision Phenomena- (1992-)