Mounir Laroussi, associate professor of electrical and computer engineering and a researcher at the Center for Bioelectrics, won attention several years ago by developing a process that used ultraviolet light to kill harmful organisms in the ballast water of ships.

Now he has invented a type of ultraviolet lamp that is designed to be ultra efficient and can be used in numerous industrial applications. His patent, titled “Electrode-less Excimer UV Lamp,” was published in late February. Laroussi, who also holds three patents in the field of plasmas and applications, was named in 2001, along with Karl H. Schoenbach, eminent scholar of electrical and computer engineering, as being among the nation’s experts in cold plasma (ionized, or electrically charged gas). Plasma is called the fourth state of matter along with solid, liquid and gas. It is at work in fluorescent and UV lighting.

Another member of the ODU faculty, Fred Dobbs, associate professor of oceanography, worked with Laroussi to develop the process by which UV light could be used to kill harmful microorganisms imported in the ballast water of foreign ships. A goal of their work was to find an inexpensive way to kill the microorganisms before the ballast water is discharged into U.S. ports and other coastal waters. The work of Laroussi and Dobbs was funded by the National Seagrant College Program of the National Oceanic and Atmospheric Administration.

Laroussi’s invention is a UV lamp with small, external ring electrodes. A disadvantage in the commercially available excimer lamps is that the outer electrode is a wire mesh that covers the cylindrical surface of the lamp, impeding the UV light. Also, the internal electrode contributes to contamination of the cylinder’s gaseous discharge, curtailing the life of the lamp.

Applications of the invention, other than for water purification, could be to disinfect surfaces, cure paint and ink, and modify the surface of polymers.