All-solid-state, tunable, single-frequency source of yellow light for high-resolution spectroscopy

We demonstrate a cw doubly resonant optical parametric oscillator that is f requency doubled in an external resonant cavity to the visible spectral ran ge. We obtained single-frequency radiation in the range 565-590 nm with as much as 3.8 mW of power, which is continuously tunable over an 18-GHz range and step tunable over 160 GHz. The source is well suited for high-resoluti on spectroscopy in the visible region. As a demonstration, we performed per sistent hyperfine spectral hole-burning spectroscopy of EU3+:Y2SiO5. Reliab le operation of the source permitted studies of the hole's lifetime over se veral hours. (C) 2001 Optical Society of America.