20^th Annual Spring Research Conference of the College of Physical and Mathematical Sciences, BYU, March 18, 2006, Provo, UT. 8 presentations by students of Allred & R. Steven Turley

Extending Our Reach into the Extreme Ultraviolet Using a Grazing Incidence Monochromator. Sarah Barton

Abstract: With the addition of the Grazing Incidence Monochromator to our current reflectometer, we have extended our reach into the extreme ultraviolet significantly. With our previous system alone, we could only produce light in the range of 1216Ã… to 304Ã…. This new system extends our range to 30Ã…. We have also shown that the compared intensity of light is much greater. This will allow us to measure more accurately the optical constants of different materials in the extreme ultraviolet, which will allow us to build multilayer mirrors to various specifications.

Oxidation Effects on the Optical Constants of Heavy Metals. Amy Baker

Abstract: The extreme ultraviolet spectrum of light is becoming increasingly important in today’s technological world. As computer features get smaller and astronomers seek new ways to explore space, applications for high energy light are appearing everywhere. Unfortunately, this spectrum of light is not very well known. In order to characterize the optical constants of light of such small wavelength, we make extremely thin films that won’t absorb the light entirely. Unfortunately with films so thin, a small amount of oxidation greatly affects the measured optical constants of the metal. This study utilizes the method of x-ray photoelectron spectroscopy to determine exact molecular composition with depth, and then uses these data to theoretically calculate the effect that oxidation has on our reflectance and transmission measurements.

Construction of an Extreme Ultraviolet Polarimeter Based on High-Order Harmonic Generation. Nicole Brimhall

Abstract: We report on a 'work-horse' application of laser-generated high-order harmonics to measure polarization-dependent reflectances for optical surfaces in the extreme ultraviolet. High harmonics provide a directional, polarized, affordable, and compact source of extreme ultraviolet light, ideal for doing polarimetry measurements in the few- to hundred-nanometer wavelength range. We describe performance of a prototype instrument and plans for the construction of a full-scale instrument.

Determining Optical Constants for ThO2 Thin Films Sputtered Under Different Bias Voltages from 1.2 to 6.5 eV by Spectroscopic Ellipsometry. William Evans

Spectrally Tunable Light Source for Remote Ocean-Color Sensing. Jacque Jackson

Computationally Modeling the Effects of Surface Roughness on Extreme Ultraviolet Multilayer Reflectors. Jedediah Johnson

Abstract: The BYU XUV Optics group has worked extensively to experimentally determine the optical constants of materials in the extreme ultraviolet. Significant discrepancies have been observed between the curves calculated from fitted constants and the actual measured data. Atomic scale roughness is a probable explanation for these differences. We are computationally modeling the reflection and transmission of these surfaces to determine the effects of roughness on optical constant calculations. Beginning with the Helmholtz equation, an integral equation approach is developed and solved by discretizing the surface and applying the Nystrom Method. These computational results will be compared to experimental reflection (Advanced Light Source, LBNL) and roughness measurements (atomic force microscope).

Fitting Optical Constants of Thin Films As Affected by Surface Roughness. Elise Martin

Abstract: Optics in the extreme ultra-violet (EUV) are becoming increasingly important. Finding the index of refraction of materials in this wavelength range can lead to technological advances. Both the real and imaginary parts of the index of refraction are important in designing optical elements in the EUV. To find these constants, reflection and transmission measurements of light off of thin films and multilayers are analyzed. However, roughness on several different length scale affects how light interacts at the interfaces of the thin films. I have been working on a MATLAB program that will calculate the optical constants of thin films taking into account this surface roughness.

Vanadium Dioxide Deposited Substrates for Thermochromic Applications. Andrew Ning

Abstract:: Thermochromic materials have the property of being able to reversibly change their optical properties from a state of reflectance to a state of transmittance for certain frequencies of light. This change is controlled by temperature. We chose to make thermochromic material by depositing vanadium dioxide on glass substrates. To produce a single phase of vanadium dioxide requires heating our substrates to over 600 °C. To meet these specifications required designing a new heater substrate. This substrate was designed and modeled using SolidWorks and machined using a water jet and end mill. The VO2 was deposited using a RF Magnetron Sputterer. The results from ellipsometry and X-Ray diffraction tests will also be discussed. Specifically we are interested in our samples’ optical properties in the microwave region.