Highly efficient InGaN-LD-pumped bulk Pr:YLF orange laser at 607 nm

We report continuous-wave orange laser operation at 607.5 nm of a 8 mm long 0.2at% Pr:LiYF4 single crystal with an improved laser slope efficiency. Using a single InGaN laser diode emitting at ∼444 nm as a pump source, an output power of ∼200 mW was achieved with a threshold absorbed pump power of ∼150 mW and a laser slope efficiency of nearly 42%. M2 factors of 1.40 and 1.28 were measured in the x and y directions, respectively, attesting to the good quality of the output laser beam.