Tunable Single-Frequency Nd:YVO₄BiB/₃O₆ Ring Laser at 671 nm

A record of 680-mW single-frequency red emission at 671.1 nm is demonstrated using a Nd:YVO₄ring laser intracavity frequency-doubled by a type-I critically phase-matchedBiB₃ O ₆crystal. Single-frequency tuning overΔ λ red ~ 1.25~nmcan be achieved with a thin etalon with reflectivity of 40%. At 1342.5 nm and with a$T=\ $2% transmission output coupler, the laser provides an optimal 1.55 W of single-frequency power.