How a Laser Jammer Works
A laser jammer detects a police laser beam, decodes the signal and transmits a reply. If this bogus return signal is at the correct frequency and the same pulse-repetition rate (PRF), it confuses the laser gun. No speed is displayed.
Most high-end custom-installed radar detectors come with laser jammers and stand-alone systems are also available, designed to be used in parallel with a windshield-mounted radar detector.