Tunable high-power narrow-spectrum external-cavity diode laser based on tapered amplifier at 668 nm

A 668 nm tunable high-power narrow-spectrum diode laser system based on a tapered semiconductor optical amplifier in external cavity is demonstrated. The laser system is tunable from 659to675 nm. As high as 1.38 W output power is obtained at 668.35 nm. The emission spectral bandwidth is less than 0.07 nm throughout the tuning range, and the beam quality factor M(2) is 2.0 with the output power of 1.27 W.