Analytical Sciences

Abstract − Analytical Sciences, 26(1), 25 (2010).

One and Two-photon Excited Optogalvanic Spectra of Argon in the Wavelength Region of 735 − 850 nm
Hideyuki MATSUTA,* Kazuaki WAGATSUMA,* and Kuniyuki KITAGAWA**
*Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Sendai 980-8577, Japan
**Ecotopia Science Institute, Nagoya University, Furo, Chikusa, Nagoya 464-8603, Japan
Optogalvanic (OG) spectra of argon in the visible to near-infrared spectral region between 735 and 850 nm were investigated using a Grimm-style glow-discharge tube, which has been widely used to obtain depth profiles of the elemental composition on various film-like samples. About 49 lines of one-photon and two-photon OG peaks were observed with a pulsed Ti:sapphire laser; these peaks were precisely assigned. Two-photon OG spectra of argon were easily observed without focusing the pulsed laser irradiation to more than 1 mJ. The excitation mechanisms of the observed argon OG spectra could be classified into 3 types: single-photon transition, two-photon transition, and two-photon stepwise transition. In addition, a pseudo-resonant effect was also found to be effective. The argon lines observed in this experiment are suitable as convenient calibration wavelength markers of pulsed tunable laser radiation.