Berlin 2001 – wissenschaftliches Programm
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A: Atomphysik
A 12: Posters Thursday (Ion/Atom/Molecule/Surface Scattering)
A 12.38: Poster
Donnerstag, 5. April 2001, 12:30–15:00, AT3
Narrowing of the absorption spectrum of metastable argon atoms in a thin discharge cell — •Masahiro Hasuo, Yoshimi Ohta, Takeshi Matsumoto, and Takashi Fujimoto — Dept. of Engineering Physics and Mechanics, Faculty of Engineering, Graduate School at Kyoto University, Yoshidahommachi Sakyoku Kyotoshi Kyoto Japan ZIP:606-8501
Narrowing of the absorption spectrum of metastable argon atoms in a thin discharge cell For an argon glow discharge in a 1mm thick cell, we have observed the absorption profile of the 1s3−2p2 (Paschen notation) line by using the external-cavity-controlled single mode diode laser. At pressure of 0.05Torr the absorption profile showed that the velocity distribution of the metastable atoms in the surface normal direction has an effective temperature of 197K. At 1.0Torr the temperature was 352K. This finding indicates that the metastable atoms having large velocity components perpendicular to the cell wall are lost upon collisions with the wall surface, and that, in low densities, themalizing collisions with ground state atoms are insufficient to compensate the loss. By using a simple model considering the spatial distribution of the generation of the metastable atoms having the velocity component v to the wall direction and the average time they spent in the cell with v, we have reproduced the spectral narrowing. The phenomena suggest the possibility of the Doppler free spectroscopy with a thin discharge cell.