904 nanometers is open territory in terms of receiving and broadcasting .... no rules against it per se

having equipment on your car intended to Jam police laser is frowned upon (and can get you an equipment violation in Ca) . ... I hesitate to use the word JAM ... but I gotta tell you there is little that is more entertaining than watching LEO scratch his head when his equipment wont lock on my car .... right until I drop below the posted speed limit

I've seen that show nearly a dozen times .... it is priceless

EDIT
No disrespect intended towards LEO (law enforcement officers) . They have an important job to do and I appreciate the risks they take on behalf of myself and others in the interest of the safety of the general public. I have friends in law enforcement and even donate to the highway patrol. Lidar (laser) is an unfair tool and I have no regrets when it comes to avoiding it.
Chris