Laser fence explained

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.

Description

A laser fence mechanism detects objects passing the line of sight between a laser source and detector. Stronger lasers can be used to injure entities passing the laser beam, as in a mosquito laser. 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]

Agricultural usage

Lasers are used to keep birds from eating blueberries by being perceived as a predator.^[5] The European Commission is funding research into a laser fence to scare away rats and other pests.^{[6] [7] [8]}

Border fences

The Indian Border Security Force (BSF) has implemented a laser wall system—called LASER Wall—along some parts of its border to stop intrusion.^[9]

In fiction

Films

In the 1992 film Fortress, prisoners are kept secured by laser walls.In the 1995 film Congo, a laser fence is used as part of other high-tech equipment to defend a camp against vicious gorillas.^[10]

Videogames

Laser walls appear frequently in videogames.^{[11] [12] [13]} The concepts of these fictional fences can be compared to other concepts like tractor or repulsor beams and force fields.

• has laser grids which you can't get past without getting a Remote Hacking augmentation, allowing you to affect it.^[14]
• has a hacker class which use viruses to shut down lasers.^[15]
• Portal 2, with laser barriers as obstacles^[16]
• ^[17]
• Titanfall 2 has laser fields to prevent access to areas.^[18]
• uses laser fences to kill off enemies.^[19]

See also

• Laser Doppler velocimetry
• Lidar

Notes and References

1. Web site: Steele . Richard K . Roudabush . Douglas E . Laser fence . United States Patent and Trademark Office . 23 July 1974.
2. Book: Thomas Petruzzellis . The Alarm, Sensor & Security Circuit Cookbook . McGraw Hill Professional . 1994 . 978-0-8306-4314-1 . 145.
3. Guth . Robert A . 2009 . Rocket Scientists Shoot Down Mosquitoes With Lasers . The Wall Street Journal.
4. News: Holden . Stephen . 4 September 1993 . Review/Film; A Futuristic Prison That Demands Escape . 11 May 2018 . The New York Times . en.
5. Web site: 26 October 2017 . Laser bird deterrent increases crop revenue by 33% . www.laserfocusworld.com.
6. Web site: 28 October 2016 . Laser fence aims to protect crops from rats and other pests . www.laserfocusworld.com.
7. Web site: LASER RAT FENCE wins €1.7m European Commission funds . The Register.
8. Bapat . Varsha . Kale . Prasad . Shinde . Vijaykumar . Deshpande . Neha . Shaligram . Arvind . 2017 . WSN application for crop protection to divert animal intrusions in the agricultural land . Computers and Electronics in Agriculture . 133 . 88–96 . 10.1016/j.compag.2016.12.007 . 0168-1699.
9. News: 28 April 2016 . 'Laser walls' activated along India-Pakistan border to plug gaps in vigil - Times of India . The Times of India.
10. Congo (1995) - shootout scene in the woods . 20 August 2018 . Toorek . Derick . Videotape . YouTube.
11. Book: Rudolf Kremers . Level Design: Concept, Theory, and Practice . 21 October 2009 . CRC Press . 978-1-4398-7695-4 . 362–.
12. Web site: Laser Fence (Object) - Giant Bomb . Giant Bomb.
13. Book: Hayley Camille . The Ultimate Player's Guide to Skylanders Trap Team (Unofficial Guide) . James Floyd Kelly . 16 October 2015 . Pearson Education . 978-0-13-421619-5 . 8–.
14. Web site: Ingenito . Vince . 19 August 2016 . Deus Ex: Mankind Divided Review .
15. Web site: Monaco: What's Yours Is Mine (Game) - Giant Bomb . Giant Bomb.
16. Web site: Chapter 8: Test Chamber 12 - Portal 2 Walkthrough . 11 May 2018 . www.thonky.com . en.
17. Web site: Short Supply - Sly Cooper: Thieves in Time Wiki Guide - IGN . IGN.
18. News: Hamilton . Kirk . The Mission That Proved Titanfall 2 Was Something Special . 11 May 2018 . Kotaku . en-US.
19. Web site: 16 March 2018 . Combining tower defense with a shooter - game design implications .