"Engage deflector shields!" is a command often heard on the bridge of sci-fi spaceships locked in battle, but could such defensive contraptions actually work? Scientists at BAE Systems believe a new type of directed energy laser and lens system that manipulates the atmosphere could make such devices a reality, and in as little as fifty years from now.
Known as the Laser Developed Atmospheric Lens (LDAL) concept, it works by simulating naturally occurring phenomena to temporarily alter small parts of the Earth's atmosphere to create lens-like structures that magnify or alter the path of electromagnetic waves, including radio signals and light. According to BAE, a lens generated in this way could be used as a type of deflector shield to protect aircraft, land vehicles, troops, and ships from assault by future high-powered laser weapons (such as future versions of Lockheed-Martin's ADAM laser weapon system).
LDAL's prime purpose, however, is to provide better electromagnetic communications by creating various naturally-occurring effects, such as the reflective properties found in the ionosphere and desert mirages. It does this by changing the reflective and refractive properties in targeted parts of the atmosphere using a high-powered laser to create highly-reflective areas (like the ionosphere) or areas where light can be bent at will (in emulation of the desert mirage).
In this way, the LDAL system would allow, say, communications operating at very high frequencies to be sent further than normally possible by recreating areas in the atmosphere that gave it properties like the ionosphere. Or it could also be used to produce localized, Fresnel-lens-like refractive areas to bend electromagnetic waves to a specific place, even when the direction was at a completely different angle to the original waves.
The system would take advantage of what is known as the "Kerr Effect" (an optical phenomenon that occurs when intense light is transmitted through media such as glass or, in this case, gases in the atmosphere, that effectively alters the refractive index of that media) to temporarily ionize a small patch of atmosphere in a way that allows the air to emulate mirrors, glass lenses, and structures like Fresnel zone plates that diffract light.
Other concepts, such as Northrop's system being developed for the US Air Force, have been mooted to control laser weapons, but this seems to be the first instance where a laser system has been proposed to create a shield to protect from laser weapon assaults. Though still very much a concept, it is this type of evaluation of what may be physically possible that is needed to spur further research.
"Working with some of the best scientific minds in the UK, we're able to incorporate emerging and disruptive technologies and evolve the landscape of potential military technologies in ways that, five or ten years ago, many would never have dreamed possible," said Professor Nick Colosimo, BAE Systems' Futurist and Technologist.