SCALING OF MICROCAVITY PLASMAS TOWARD 1 um: SCIENCE AND ENGINEERING OF SPATIALLY-CONFINED, LOW TEMPERATURE PLASMAS

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

0853739 Eden This research aims to produce ultra-small-sized plasmas as small as 1 micrometer in diameter and then to determine their properties using laser and other optical techniques. Microplasmas, operated at sizes of 0.5 mm and below, offer exciting new possibilities for plasma applications and scientific study. They can have very high power density yet can operate continuously at atmospheric pressure and higher. Recent studies have shown that plasmas so confined behave quite differently from macroscale plasmas such as in a fluorescent lamp or a neon sign. It is expected that as plasmas are reduced to sizes previously unattainable, they will become increasingly cold and dense and resemble a liquid. Microplasmas will be generated within cavities having a characteristic dimension below 20 µm. Electron and neutral gas temperatures, and electron and excited state number densities will be studied primarily by optical techniques such as inverse bremsstrahlung and laser-induced fluorescence. Spatially resolved studies will also be conducted with a recently constructed vacuum/optical system having an integrated microscope. By using plasma channels with cross-sectional dimensions approaching those of conventional optical waveguides (~2-10 µm), new opportunities are created for monitoring the microplasma optically by coherent and incoherent processes such as Raman scattering, and the results can be compared with simulations. Laser probing experiments will also investigate the interaction between a gas-phase plasma and an e--h+ plasma in hybrid microplasma/semiconductor devices. A key component of this program is educational outreach, critical aspects of which focus on undergraduates and a close interaction with science teachers in a semi-rural school district in east central Illinois, primarily at the junior high school level. At least one science teacher will participate in research each summer, developing plasma/optical experiments for students to be integrated into both the junior and senior high school curricula. Such outreach is meant to attracting more women and underrepresented minorities to this field, while increasing the interest of all precollege students in the physical sciences.