Doppler-Free Stimulated-Emission Spectroscopy and Secondary Frequency Standards Using an Optically Pumped Laser

Abstract

A new Doppler-free stimulated-emission technique using an optically pumped laser with applications in spectroscopy and optical frequency standards is reported. An argon-laser-pumped cw ${\mathrm{I}}_{2}$ laser is used to demonstrate the technique as well as measure the complete hyperfine structure of the ${\mathrm{I}}_{2}$ $B{{\mathrm{O}}_{\mathrm{u}}}^{+}\ensuremath{-}X{^{1}\ensuremath{\Sigma}_{\mathrm{g}}}^{+}$ (43,83) $P(13)$ line. Hyperfine coupling strengths obtained for the $X{^{1}\ensuremath{\Sigma}_{\mathrm{g}}}^{+}{v}^{\ensuremath{'}\ensuremath{'}}=83$, ${J}^{\ensuremath{'}\ensuremath{'}}=13$ level are $\mathrm{eQ}{q}^{\ensuremath{'}\ensuremath{'}}=\ensuremath{-}1550.1\ifmmode\pm\else\textpm\fi{}0.5$ MHz and ${C}^{\ensuremath{'}\ensuremath{'}}=59\ifmmode\pm\else\textpm\fi{}5$ kHz. In addition, the ${\mathrm{I}}_{2}$ laser has been actively stabilized to within 1 kHz of the observed line center of an ${\mathrm{I}}_{2}$ hyperfine component.