It is legal to build, own and use. Just not in public. The first time you cause damage to someone or someone's property you are legally, and/or criminally liable.
Hey! Great way to burn out the receiver in a cop's laser driven speed measuring instrument.
I am going to build both the laser, as well as the flashlight. I'll put the flashlight on my bike for a headlight.
Long time, no see AL! Nice to know that you are still around.
How did your eotvos experiment go? Get good results?