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Physics & Astronomy

Colloquia

Upcoming Colloquia

Weekly colloquia are hosted by the Physics & Astronomy Department of Brigham Young University. Colloquia are held regularily during Fall and Winter semesters on Wednesdays at 4:00 PM in BYU's Eyring Science Center. Refreshments are typically offered and all who wish to attend are welcome.
Extreme Ultraviolet Polarimetry with Laser-Generated High-Order Harmonics: Characterization of Copper and Uranium
Wednesday, November 11, 2009
C215 ESC 4:00 PM
Niki Brimhall Department of Physics and Astronomy, Brigham Young University
Department of Electrical and Computer Engineering, University of Utah
Summary:
Abstract:
The extreme ultraviolet (EUV) wavelength range (i.e. 10-100 nm) has become important in fields such as short-wavelength computer chip lithography, space-based astronomy, and high-resolution microscopy. For example, in the past ten years, researchers at BYU have developed EUV optics for use on three satellites including NASA’s IMAGE satellite. The IMAGE satellite is currently imaging the near-space around Earth in the EUV using a uranium-silicon multilayer mirror designed and built by students at BYU. However, when building this mirror, researchers found that it did not reflect like they expected it to, due to lack of accurate material optical-constant values. It turns out that there are many materials whose optical constants are not well known in this wavelength range.

Here we present a new instrument, designed and built at BYU, that uses a high-intensity infrared laser to produce EUV light useful for characterizing material optical properties. We have used this instrument to measure the optical properties of uranium for the first time in this wavelength range. We also found that previously published optical constants for copper metal, a material important to computer-chip lithography, were measured incorrectly in the EUV.
 
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