Single-mode continuous-wave Cr(3+):LiSAF ring laser pumped by an injection-locked 670-nm broad-area diode laser

We report on an efficient continuous-wave Cr(3+):LiSrAlF(6) ring laser pumped by the near-diffraction-limited output of an injection-locked 665-nm broad-area diode laser. With an absorbed pump power of 120 mW the ring laser generates 22 mW of single-mode 855-nm radiation with a spectral linewidth of less than 10 MHz. Unidirectional operation and longitudinal-mode control of this ring laser is achieved by injection of 855-nm diode-laser radiation into the ring cavity. Optical feedback of ring-laser radiation into the diode laser narrows the diode laser's linewidth and locks its frequency to a resonance of the ring resonator.