Smaller side on doping or length? My hope was to not going that tight on input or even do side pumping... Is it already lost? :-)
For first tests my intention was to go with flat-flat. This way I can start with 99.5% dichroic mirrors I already have. Crystal AR coatings 0.5% for both...
I currently have 2 Pr:YLF crystals at hand. Going to try them in the following months. We'll see if I can get any orange/red out of them :-)
But their fluorescence is much weaker than I expected - I can see the Pr lines but that's about it, probably my pump laser had slightly wrong...