LIGO is an observatory in Europe. It is 2 long tunnels at right angles with mirrors at the ends. A laser is sent to a beam splitter which sends the light down both tunnels - when it comes back it is combined and sent to a detector. The idea is that if a graviton passes, (or a gravity wave) at least one beam will be influenced and an interference pattern will be seen at the detector.
Jitter is what they try to remove from the system. so, for example, they isolate the system so that if a bus travels down the street in a town 5km away, it will not jiggle the beams.
They isolated the hell out of it all and the jitter they were left with is pretty much smack on what the basic Planck constant would be if the universe is a hologram coating the limits of the observable universe.
Hope that helps... My apologies - I thought any discussion of holograms/holographs would presume a certain amount of the basics about the subject. Not being insulting, OK? Sometimes I make assumptions that are not justified.