Fluorescence-based intracavity laser spectroscopy and the electronic structure of NiH

We describe a fluorescence-based continuous-wave (cw) laser intracavity spectrometer which provides tunable cw laser light of high intensity (greater than 200 W/cm2) over a large spatial region (greater than 3×10−2cm3), greatly increasing the amount of observable side fluorescence and facilitating saturation of weak optical transitions as compared to extracavity spectroscopy. Using examples (saturation dip spectra of the hyperfine structure of the rare isotopomer 61NiH and dispersed fluorescence spectra terminating in previously unobserved low-lying states of 58NiH), we illustrate the capability of this spectrometer to rapidly and efficiently gather information crucial to the verification of electronic structure models.