A laser fence or laser wall is a mechanism to detect objects passing the line of sight between the laser source and the detector.[1][2] Stronger lasers can be used to injure entities passing the laser beam.[3] In fiction, laser fences may have the ability to stop intruders by blocking or injuring them.
A laser fence mechanism detects objects passing the line of sight between a laser source and detector.[1] Stronger lasers can be used to injure entities passing the laser beam, as in a mosquito laser.[3] Fictional uses of laser fences often extend the concept so that fences may have the ability to prevent intruders by blocking or injuring them.[4][5][6][7][8]
Lasers are used to keep birds from eating blueberries by being perceived as a predator.[9] The European Commission is funding research into a laser fence to scare away rats and other pests.[10][11][12]
The Indian Border Security Force (BSF) has implemented a laser wall system—called LASER Wall—along some parts of its border to stop intrusion.[13]
In the 1992 film Fortress, prisoners are kept secured by laser walls.[4] In the 1995 film Congo, a laser fence is used as part of other high-tech equipment to defend a camp against vicious gorillas.[14]
Laser walls appear frequently in videogames.[15][16][17] The concepts of these fictional fences can be compared to other concepts like tractor or repulsor beams and force fields.