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