2010 Heidi Dumais Spring Research
Measurements of the Complex Index of Refraction for Uranium Dioxide in the Extreme Ultraviolet
The BYU Extreme Ultraviolet research group recently visited Berkeley’s Advanced Light Source to measure reflectance and transmittance in the extreme ultraviolet for a diode sputtered with a uranium dioxide film. We left half of the diode uncoated. The reflectance data for the coated side helps determine the actual thickness of the film (about 20 nm). Using this thickness and fitting the transmission data to a model yielded the complex part of the index of refraction for uranium dioxide in the extreme ultraviolet region at every tenth of a nanometer in wavelength. Similar analysis on the uncoated data provided the thickness of the silicon dioxide film and the "dead layer" for the diode. These values provide researchers with valuable information for modeling, design and fabrication of optical systems in the extreme ultraviolet.