Measurement of the populations of metastable levels in gadolinium vapor by diode laser-based UV and near-IR absorption spectroscopy

摘要

The metastable populations of gadoliniurn atoms, which were generated by an electron beam gun, were measured by diode laser-based absorption spectroscopy. Transitions originating out of the ground and low-lying metastable levels were investigated in the spectral range of 390-394 nm. A tapered semiconductor power-amplifier which was seeded by a single-mode external-cavity diode laser was used as a fundamental light source for the second-harmonic generation in the ultraviolet wavelength range. The population appears to be frozen at an atomic excitation temperature of -600 K, which is about 1/4 of the heated surface temperature. The results obtained from the ultraviolet absorption spectra are compared to those obtained from the near-IR absorption spectra with wavelength ranges of 673-692 and 773-775 nm. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 21]