Introduction
Laser weapons are tactical beam weapons utilising chemical or solid-state lasers to disable or destroy military targets at distances from a few hundred meters to many hundreds of miles. "Laser" is an acronym for Light Amplification by Stimulated Emission of Radiation.
Despite taking more money and time than initially thought, military laser systems are fast becoming a reality, and it is predicted they will be in use on the battlefield by the United States and Israel within this decade. This article explains how lasers work, then outlines key laser weaponry projects and what they might show us about the future of tactical beam weapons.
The science of lasers
Common light sources such as light bulbs emit coherent beam of near-monochromatic light.
Stimulated emission occurs when a photon passes an electron in an excited energy state, causing it to relax to its ground state and emit another photon. Stimulated emission produces laser light because the photon that stimulates an excited electron into emitting another photon must have a frequency that matches the energy difference between the ground and excited state of the electron: this means the emitted photon has the same frequency and phase as the passing photon, thus adding to a coherent beam.
The two main types of laser being researched for military use are chemical-based and solid-state lasers. Chemical lasers are objectionable because of their size and the quantity of potentially toxic chemicals needed to power them. Solid-state lasers are generally smaller in size and can be powered by electricity, but have problems with overheating.
ABL: The Airborne Laser
Several companies in the United States are attempting to build laser weapon systems. One of the more successful to date is the ABL, currently being researched by Northrup Grumman and Lockheed Martin. The initial objective of the project is to mount a chemical (oxygen-iodine) based laser on board a 747 jumbo jet; to date the project has successfully fired the laser on the ground, and hopes to be conducting airbone tests between 2006 and 2009.
Ideally the project aims to miniaturise the laser to the point that a 100kW laser can be mounted on a fighter jet such as the US-UK JSF. Such a laser would be powered by electricity generated by the plane’s turbofan engine, and will be used for air defence and precision strikes on ground targets.
THEL
The Tactical High Energy Laser (THEL) project was begun as a joint US-Israel initiative to counter rocket attacks from guerillas in neighbouring Lebanon and Gaza. Its precursor was the Nautilus laser weapons system, which successfully destroyed a rocket in flight in 1996. Since then the THEL system has been reduced in size, and will eventually be deployed as a mounted weapon on MTHEL).
THEL is being developed at the High Energy Laser Systems Test Facility (HELSTF) in New Mexico. It is capable of intercepting Katyusha and Kassam missiles, and was demonstrated capable of shooting down 25 Katyushas both singly and in salvos. The IDF hope to see them in service by 2007, and they will also be used by the US Army. Mobile ground-based laser systems will ideally be used to shoot down incoming artillery or mortar attacks, or possibly against other strategic targets.
MIRACL
MIRACL, the Mid-Infrared Advanced Chemical Laser, is the only successful weapon developed as part of the how a war is fought”>jus in bello" of nations engaged in armed conflicts: deciding when it is fair and reasonable to deploy lethal laser strikes against (extremely) remote targets.
In the future, laser weapons might certainly expand into space, to which they are ideally suited. Atmospheric interference and unclement weather conspire to diffract and diffuse a laser beam’s coherence, dramatically reducing its potential, whereas a space-space laser weapon would not suffer these effects to anything like as significant a degree. Satellite platforms have been considered for ballistic missile defense, and also could be used to conduct precision ground-strikes against any target on the Earth’s surface.
Laser weapons, being most effective in space, would be ideal for spacecraft or station defense, whether against meteorites and other space debris, or hostile forces. A "planetary defense" system could also make use of high powered, extreme-range laser weapons to protect the Earth from possible external threats.