The summary article completely omits the description of how to do the feedback. A laser (and FEL) need a cavity for coherent light emission (typically with mirrors), otherwise we just have spontaneous emission (which is incoherent). So how does one make a gravitational wave cavity, or even a GW mirror?
A better name should be graser, but it is already taken [1]. Gaser doesn't sound as cool. Any other option?<p>[1] <a href="https://en.wiktionary.org/wiki/graser" rel="nofollow">https://en.wiktionary.org/wiki/graser</a>
Do you get limits on how tight the beam can be compared to the emitter size, like with RF and visible?<p>What about diffraction patterns and other things that normal lasers do?