Crystal oscillators are loosely divided from the frequency they perform at and whether they are elementary oscillators—work for the frequency marked within the can or at even multiples of that (overtone oscillators). Substantial-repetition-amount and superior-electrical power picosecond regenerative amplifier based on just one bulk Nd:GdVO4 crystal PDF Structure of resonators https://www.hxcrystals.com/seokeywords/bulk-crystal-oscillator.html