Abstract

We have demonstrated a stable and widely tunable diode laser locked to the hyperfine Zeeman-absorption D₂ lines of Rb. We locked the laser both to the linear-absorption lines and to a new, stable Doppler-free absorption structure. The new Doppler-free absorption spectrum appears in the saturated, Zeeman-shifted ⁸⁵Rb-D₂ lines when linearly polarized light is used. This new structure provides a stable frequency reference. The linear Zeeman spectra of ⁸⁵Rb and ⁸⁷Rb, which are obtained with circularly polarized light, provide widely tunable frequency references. The range of applied longitudinal magnetic fields used extends up to 1000 G.

© 1995 Optical Society of America