A laser has become a vital weapon in the British Army's operations in Afghanistan. It doesn't burn its target to a cinder; in fact, its function is saving lives. The Green Laser Optical Warner, or GLOW, made by Thales is used to stop anyone approaching a checkpoint or patrol. Unusually for a weapon, the safety of the target is a key design consideration.
Weighing about a kilo, GLOW is a lot chunkier than your average laser pointer, but the effective range of over three hundred metres is more than most laser pointers too. GLOW fits under the barrel of a rifle, and is described as an "escalation of force option", providing an intermediate step between shouting at someone to stop and shooting at them. The brilliant light will get anyone's attention whatever language they speak, and the dazzle effect will prevent most people from moving forward. GLOW has wide and narrow beam settings.
"The narrow beam diameter is around half a meter at fifty metres, wide beam will fill a car windscreen," says Denise Clarke, Communications Director at Thales. A Pulse setting causes the beam to flash, making it even more noticeable.
According to a company spokesperson, British forces have used GLOW in at least 20 confrontations when lethal force might otherwise have been employed, potentially preventing an innocent person from being shot in every case. Every time someone is shot, and the likelihood of attacks on British forces increases, making non-lethal devices like GLOW an essential tool for this type of conflict.
US forces have been using laser dazzlers in Iraqand Afghanistan for years, but safety considerations were low on the list of priorities. Initially, some US soldiers simply bought their own high-powered laser pointers, or used lasers supplied for other tasks such as designating targets for airstrikes. But such lasers may not be eye safe and can cause injuries -- there have been a number of reports of US troops being hospitalised with eye injuries following careless use of dazzlers, and there may be many more unreported cases among local people. Being blinded may be better than being shot, but permanent eye damage is not going to improve anyone's attitude towards foreign troops.
One of the lasers used by US forces is the GBD-III made by Meyers, which has a Nominal Ocular Hazard Distance (NOHD) of almost a mile, meaning that it is potentially hazardous at shorter ranges. While American forces are now using less powerful lasers, even the latest GLARE MOUT lasers ordered by the US Marine Corps have an NOHD of almost thirty metres.
By contrast, GLOW has a Nominal Ocular Hazard Distance of less than 10 metres, so you would have to be that close before there was any risk. Even within that range it has been designed to minimise the risk of permanent damage, and it's the first laser to get legal, medical and ethical clearance with the Ministry of Defence. GLOW has two independent safety systems which ensure the output is within the required levels.
That doesn't mean it's totally safe; this is still a Class 3B laser (described as "Hazardous") and Thales material cautions that it is non-damaging "when used in accordance with Manufacturers Operating Instructions." Anyone who tries turning GLOW on and looking into the beam to see how bright it is liable to regret it.
While GLOW does have a dazzling effect, and would certainly make life harder for someone trying to driver a suicide bomb at a checkpoint, its main function -- as the name implies -- is simply to warn.
British laser weapons have not always been so innocuous. During the Falklands conflict some Type 22 Frigates were fitted with the Laser Dazzle Sight or Outfit DEC, though this was not revealed until some years later. It was designed for use against air attack, temporarily blinding a pilot and preventing him from aiming effectively, and quite possibly causing him to crash during a low-level attack run. The Laser Dazzle Sight was reportedly used in the Falklands, and there is at least one report of an Argentine pilot being driven away from HMS Argonaut by a brilliant light. The last version DEC 3, had a reported range of five kilometres.
However, in 1995 the UN issued the Geneva Protocol on Blinding Laser Weapons, which outlawed lasers that were deliberately designed to cause blindness. High-powered lasers such as the Laser Dazzle Sight could be considered blinding lasers, especially if used at close range, and the equipment appears to have been withdrawn.
Since then there have been many attempts to develop non-lethal dazzling lasers which are both effective and harmless. This is a tough challenge because of the variables involved; something which is bright enough to dazzle at a 1,000 metres is likely to be damaging at 50. And the effect on they eye varies with the lighting conditions. Headlights which look blinding at night when your pupils are dilated can be barely noticeable on a sunny day.
Rather than turning up the brightness, some developers are trying to enhance the effect with pulsing. This does not trigger photosensitive epilepsy -- the flicker rates are too low for that -- but to cause other effects, in particular dizziness and nausea. There is some disagreement among scientists whether this is really possible. Laser Energetics, makers of the new "Laser Dazer" being tested by police in Seattle, claim that their device can cause something like motion sickness. In the case of GLOW, the flashing setting is simply to make it more obvious and attract attention.
The use of laser dazzlers by both military and police is set to increase, and GLOW is an important step forward as it was designed with safety as the main consideration. Any device which could cause permanent eye damage may cause a lot more problems than it solves, and is likely to be left at base. GLOW is a warning signal which is backed by lethal force if necessary, and sometimes that warning may be all that's needed.
This article was originally published by WIRED UK
