Microplasma Channels and Large Arrays: Applications to Photomedicine, Microlasers, and Reactors on a Chip

Under the support of AFOSR grant no. FA9550-07-1-0003, our laboratory at the University of Illinois has pursued the science and applications of microcavity plasmas, both as single devices and in the form of large arrays. Because of its unique properties, microplasma technology has (we believe) profound implications for photonics and electronics, with applications ranging from general lighting to biomedical diagnostics. During the past 3 years, the following milestones have been reached under this AFOSR program: 1. The plasma bipolar junction phototransistor (PBJT) has been discovered. A hybrid plasma/semiconductor device in which a microplasma replaces the collector in an otherwise conventional npn transistor, the PBJT is capable of switching and modulating a plasma with a base-emitter voltage of < 1V. 2. Large arrays of microcavity plasma devices have been fabricated from a single sheet of aluminum foil by a sequence of wet chemical processes in which the electrodes and interconnects are formed automatically while simultaneously being encapsulated in alumina. 3. The ability to reproducibly fabricate microcavities of controllable cross-section in Al or Al2O3 has been demonstrated. Arrays of cavities having a parabolic cross-section and all dimensions specified to within plus or minus 4% can now be fabricated over an area of hundreds of square centimeters. 4. Ellipsoidal microcavities and parabolic cross-section microchannels have been fabricated in glass and crystals (such as CaF2) by a nanopowder blasting technique developed in our laboratory. 5. Microplasma lamps of large area (greater than 100 square centimeters) have been fabricated in Al wire fabric (screen) and characterized. 6. As a direct result of AFOSR funded research, a new company (Eden Park Illumination) was launched in 2007. Today, the company employs eight individuals full time.