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

本研究旨在生产直径小至1微米的超小尺寸等离子体，然后利用激光和其他光学技术确定其特性。微等离子体的运行尺寸为0.5毫米及以下，为等离子体应用和科学研究提供了令人兴奋的新可能性。它们可以具有非常高的功率密度，但可以在大气压或更高的压力下连续工作。最近的研究表明，如此受限的等离子体与荧光灯或霓虹灯等宏观等离子体的行为完全不同。预计随着等离子体缩小到以前无法达到的尺寸，它们将变得越来越冷，密度越来越大，像液体一样。微等离子体将在特征尺寸小于20µm的腔内产生。电子和中性气体温度，以及电子和激发态数密度将主要通过光学技术，如逆韧致辐射和激光诱导荧光来研究。空间分辨研究也将使用最近建造的集成显微镜的真空/光学系统进行。利用截面尺寸接近传统光波导（~2 ~ 10µm）的等离子体通道，为利用相干和非相干过程（如拉曼散射）对微等离子体进行光学监测创造了新的机会，并将结果与模拟结果进行了比较。激光探测实验还将研究混合微等离子体/半导体器件中气相等离子体和e- h+等离子体之间的相互作用。该计划的一个关键组成部分是教育推广，其关键方面侧重于本科生，并与伊利诺伊州中东部半农村学区的科学教师密切互动，主要是初中水平。每年夏天至少有一名科学教师参与研究，为学生开发等离子体/光学实验，并将其整合到初中和高中课程中。这样的推广是为了吸引更多的女性和代表性不足的少数民族进入这一领域，同时增加所有大学预科学生对物理科学的兴趣。

0853739EdenThis 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.