The U.S. military is developing PEP using an invisible laser pulse which ablates the target's surface and creates a small amount of exploding plasma.
In 2003, a US military review[citation needed] reported that the electromagnetic radiation produced by PEPs cause pain and temporary paralysis in animal experiments.
The United States Special Operations Command FY 2010 plans included starting development on a Counter UAV Pulsed Energy Projectile.
The controversy and the fear of public opinion to see it turned into a torture tool that wouldn't leave any physical evidence on the victim ended the official program.
Cooper kept on studying effects of laser-generated plasma pulse on pain receptors and published a paper in 2008 titled "Frequency Dependent Interaction of Ultrashort E-Fields with Nociceptor Membranes and Proteins".