Physica Scripta
Two-photon two-color diode laser spectroscopy of the Rb 5D5/2state
Timothy T. Grove, V. Sánchez-Villicaña, B C Duncan, S. Maleki, P. L. Gould
Abstract
We report on spectroscopic measurements of the Rb 5 D 5/2 state performed using two-photon excitation with a resonant intermediate state. With the two beams (5 S 1/2 → 5 P 3/2 at 780 nm and 5 P 3/2 → 5 D 5/2 at 776 nm) counterpropagating, the spectra are Doppler-free and the signals are very robust, even in a room temperature vapor. This is due to the near match of the transition wavelengths. The 5 D 5/2 hyperfine constants have been measured and compared to previous determinations. We have also performed the excitation in a sample of laser-cooled atoms and compare these results to those obtained at room temperature. The fact that the 5 P 3/2 → 5 D 5/2 transition is narrow, robust, diode-laser accessible, and relatively immune to AC-Stark shifts, may make it a promising candidate for a frequency reference at 776 nm.