Optogalvanic sub-Doppler spectroscopy in titanium

Abstract

The a 3P0-y 3D10 Ti I transition at 592.2 nm was investigated by using a hollow-cathode discharge. Sub-Doppler resolution was obtained by combining optogalvanic detection with saturation spectroscopy and the non-linear Hanle effect. The upper state Lande factor was also determined by Zeeman intermodulated spectroscopy.

Nonlinear Hanle effect in an open V-type level system

“…An experimentally interesting case is the one in which ω = 0 and any value of δω. This corresponds, for example, to experimental curves obtained by tuning a single frequency laser to the centre of the line profile and detecting fluorescence (or the optogalvanic signal (Cruz et al 1994)) as a function of a uniform magnetic field. These types of curve have been considered theoretically by for a closed J l = 0 → J u = 1 system.…”

“…This corresponds, for example, to the experimental case of the spectroscopy of excited levels of a gas in an electrical discharge, such as in a hollow cathode lamp or a gas laser tube (for example a HeNe or Ar + laser). One particular experiment, which we reported previously and which motivated the present analysis (Cruz et al 1994), involved NLHE spectroscopy on the 3 P 0 -3 D 1 transition of titanium, sputtered in a hollow cathode lamp. Both the lower level of this transition, at 8400 cm −1 , and the upper one, at 25 300 cm −1 are populated by the electrical discharge.…”

“…We consider first a homogeneously broadened line and then a Doppler broadened one, in the usual limit of ω Doppler γ homog . Our analysis can thus be applied to transitions between excited states in a gas and was motivated by high-resolution spectroscopy experiments in hollow cathode discharges (Cruz et al 1994). One particular interest is in laser transitions, where population inversion can be achieved in arc discharges (for example in Ar + lasers) or hollow cathode ones (Mirage et al 1996, Cruz et al 2001, by changes in the excitation or decay rates induced by controlling current and pressure.…”