Frequency-tunable 500-mW continuous-wave all-solid-state single-frequency source in the blue spectral region

A compact source of stable cw single-frequency radiation at 473 nm has been realized by second-harmonic generation of a diode-pumped miniature Nd:YAG ring laser operating on the (4)F(3/2) - (4)I(9/2) laser transition. By use of potassium niobate (KNbO(3)), single-longitudinal-mode output powers of 500 mW cw with high stability and maximum optical-to-optical conversion efficiencies >81% are achieved. An external semimonolithic cavity permits mode-hop-free frequency tuning of blue radiation over as much as 20 GHz.