DIODE-LASER SPECTROMETER AT 493 NM FOR SINGLE TRAPPED BA+ IONS

A diode laser spectrometer at 493 nm is described, which is especially suited for spectroscopy of single trapped Ba+ ions. Frequency doublin g of a 100 mW diode laser at 986 nm results in up to 60 mW output powe r at 493 nm in a bandwidth of less than 60 kHz with respect to the cav ity used for locking. Reference frequencies of 18 spectral lines of Te -2 near the 493 nm resonance of Ba+ have been measured using modulatio n transfer spectroscopy. The fluorescence excitation spectrum of a sin gle Ba+ ion, measured with this laser, exhibits well-resolved dark res onances, which confirms the versatility of the system for quantum opti cal experiments.