How Laser Jammers Work

So, how do laser jammers (also referred to as laser shifters or laser scramblers) actually work? Perhaps you have a friend who has installed laser jammers on his car, or you’ve seen them on the BMW in front of you in traffic. Do laser jammers really work?, people ask. How is that even legal?, they wonder.

Laser jammers really DO work, and in some states they aren’t legal! In most US states, however, they are just as legal as radar detectors.

If you’re just joining us, you may want to read up on the two previous articles:

What are Laser Jammers?
How Do Police Laser Guns Work?
How Do Police Laser Guns Work?
How Do Police Laser Guns Work?

As we previously established, police laser (LIDAR) guns measure speed by using infrared light to measure distance a few hundred times (in just a few seconds). The genius of police laser guns, as opposed to radar guns, are that the laser beam of light is concentrated into such a small area that it can only target one car at a time. Officers want to be able to pinpoint one specific car and the laser gun’s small beam allows them to do so. Light beams expand as they travel; they may start as small as a pin when they exit the laser gun. However, even after 1000 feet, the beam is only about six feet wide and still small enough to target a single car.

Essentially, the laser jammers just shine back light at the laser gun! The laser gun has no idea of knowing which light it sent out, and which light the laser jammers are sending out, so it can’t get a speed reading. Of course, the light has the be the same kind of light emitted – in this case, infrared light at a wavelength of 904 nanometers (nm). Also, it can’t be just as bright as the laser gun itself, it has to be brighter – way brighter! Just imagine that someone is shining a flashlight at you in the dark. You then respond by shining a floodlight back at them – your light will far outshine theirs and they’ll be blinded.

The earlier generation of laser jammers did only this – flooded the police laser gun with much more light on the same wavelength. However, this proved intermittently effective – many times it worked well, but sometimes it would fail. In this business, you need to be 100% effective or you’ll be paying for a lot of tickets! Police laser gun manufacturers also got a bit wise to the trick and began implementing ‘jam codes’ that tell the officers that the gun is being jammed.

In response, laser jammer manufacturers pulled another trick out of their sleeve. Remember the laser gun pulse rates we talked about in How Police Laser Guns Work? Guns often run at certain pulse rates, like 140pps and 250pps (pulses per second). New laser jammer systems began emitting the jamming light at the same pulse rates as the guns themselves! Now, the police laser guns are receiving extremely bright light, at the same wavelength, and at the same pulse rate.

As they once said in a game called Pokemon – it’s super effective!

So there you have it – now you know how laser jammers work.

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