Laser jamming isn't illegal, at this time. However, I'd bet that your local LEO might take a dim view of it if discovered.
Despite this, I have had a laser jammer on both my cars for several years now, and it DOES work. I've only gone through a laser trap a few times, but it sure gets your attention when you do! I check my speed, adjust if necessary, and then turn it off so they can get a reading.
I don't use a laser jammer on the bikes, YET, and I've only gone through a laser trap twice (Atlanta GA, and I-75 in FL) in the last three years, probably because I prefer to ride where there's not much traffic. However I DO use a radar detector on my bikes, never leave home without them!
The latest RADAR uses "POP", which is very short duration pulses that many radar detectors don't even detect. By the time you get an alert, it's too late to adjust your speed, unless your detector detects POP. I have, and have used, both the Valentine One and the Escort 8500K50. The Escort falses way too often when POP mode is turned on, so I keep it off and take my chances. I just got another Valentine to replace it, so the Escort is being retired.
I can't say enough good about the Valentine detector and his customer service. I've been using them for about three years now, and sent two of them in this winter to be upgraded to detect POP. They were both getting a bit nasty looking, having been on the bikes for thousands of miles, including some heavy rain (I take them off during heavy rain, but they seem to get a bit wet before I get that done) They came back looking like new, and work better than ever.
Of course, the best defense against a speeding ticket is to ALWAYS ride or drive at or below the speed limit, but the down side of that is you're likely to become the hood ornament on somebody's vehicle.