Isolator-free 60 W diamond Raman laser at 607 nm

We report an intra-cavity frequency doubled diamond Raman laser operating at 607 nm. A z-fold cavity design was configured to prevent back reflections into the fiber amplifier, which avoided the use of isolators in the pump beam path. A maximum output power of 60 W was generated in two output beams at an optical conversion efficiency of 28% from the 1045 nm pump. A maximum single-beam output power of 40 W was obtained using a highly reflecting end mirror for the visible. Output power and single frequency stability are negatively impacted by an increasing role of stimulated Brillouin scattering at output powers above 10 W.