Crystal oscillators are loosely divided by the frequency they function at and whether or not they are basic oscillators—do the job on the frequency marked on the can or at even multiples of that (overtone oscillators). We current a Nd:GdVO4 bulk crystal oscillator with >70 WTEM00 laser output based on https://www.hxcrystals.com/seokeywords/bulk-crystal-oscillator.html