The two devices under development by the civilian National Institute of Justice both build on knowledge gained from the Pentagon's controversial Active Denial System (ADS) - first demonstrated in public last year, which uses a 2-metre beam of short microwaves to heat up the outer layer of a person's skin and cause pain.Like the ADS, the new portable devices will also heat the skin, but will have beams only a few centimetres across. They are designed to elicit what the Pentagon calls a "repel response" - a strong urge to escape from the beam
The NIJ's laser weapon has been dubbed Personnel Halting and Stimulation Response - PHaSR - and resembles a bulky rifle. It was created in 2005 by a US air force agency to temporarily dazzle enemies but the addition of a second, infrared laser makes it able to heat skin too.
The NIJ is testing the PHaSR in various scenarios, which may include prison situations as well as law enforcement. The NIJ's portable microwave-based weapon is less developed. Currently a tabletop prototype with a range of less than a metre, a backpack-sized prototype with a range of 15 metres will be ready next year, a spokesperson says. The truly portable mini-ADS could prove the more useful, as microwaves penetrate clothing better than the infra-red beam, which is most effective on exposed skin. Although the spokesman says: "In LEC [Law Enforcement and Corrections] use there is always a little bit of skin to target." (Source: New Scientist)