Optical double resonance with laser-induced fluorescence detection

1982 ◽  
Vol 307 (1500) ◽  
pp. 603-615 ◽  
Keyword(s):  
Free Radicals ◽  
Laser Beam ◽  
Hyperfine Structure ◽  
Fluorescence Detection ◽  
Molecular Species ◽  
Double Resonance ◽  
Laser Induced Fluorescence ◽  
Intense Laser ◽  
Laser Induced Fluorescence Detection ◽  
Optical Double Resonance

The saturation of level populations induced in a molecule by an intense laser beam may be probed by a second beam at the same or a different frequency. A number of schemes have been based on this principle for simplifying complex spectra or for achieving sub-Doppler resolution. Fluorescence detection provides the sensitivity for studies on free radicals and other transient molecular species. The two beams may be provided by two separate lasers, or by sideband modulation of a single laser. These techniques are reviewed. Emphasis is placed on recent studies of hyperfine structure, of Stark splittings, and of Zeeman splittings.

scholarly journals Angular Selection of Products by Use of Saturated-Absorption Techniques in the Cs(7P)+H2→CsH+H​ Reaction

1990 ◽  
Vol 10 (5-6) ◽  
pp. 377-388 ◽  
Author(s):  
J. -M. L'Hermite ◽  
G. Rahmat ◽  
R. Vetter
Keyword(s):  
Laser Beam ◽  
Fluorescence Detection ◽  
Laser Frequency ◽  
Laser Induced Fluorescence ◽  
Laser Beams ◽  
Saturated Absorption ◽  
Laser Induced Fluorescence Detection ◽  
Tunable Dye Laser ◽  
Beam Experiment ◽  
Selection Of

The Cs(7P)+H2→CsH+H​ reaction is studied in a crossed-beam experiment with laser-induced fluorescence detection of CsH products. The usual flux (≈50mW/mm2) which is delivered by the C.W. tunable dye laser used in the experiment is enough to saturate the absorption by CsH products. Then, by crossing twice the laser beam through the collision volume (counterpropagating beams), one realizes the conditions of saturated-absorption experiments: when the laser frequency is tuned to a resonance frequency of CsH products, a defect to absorption occurs for these products which scatter in the collision plane and a "saturation dip" appears at the center of the corresponding fluorescence profile. Application of this technique to crossed-beam experiments can lead to the selection of product molecules which scatter in any definite plane. A different geometry of the laser beams (bent beams) is proposed to select molecules which scatter in any definite direction: it could be applied to detect an asymmetry in the scattering of the products with respect to the collision axis, when a particular preparation of the reagents is realized.

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