Abstract by Ethan Edwards
Physics and Astronomy
The Effects of Roughness on Reflection
When the wavelength of incident light is comparable with the length scale of a surface’s roughness, physical and geometrical optics approximations of reflectance fail. Since even the smoothest surfaces have nanometer-scale roughness, finding alternatives to these approximations is important for wavelengths between 1 and 30 nm. To directly calculate far-field reflectance, one can use a boundary integral equation derived from Maxwell’s equations. I will outline an approach I am using to calculate reflectance with this method which removes the deficiencies of other approximations. I will outline the theory behind this approach and its numerical implementation. Previous research indicates that rms surface roughness greater than 1% of the incident light’s wavelength noticeably affects reflectance. I will show how I plan to use this calculation to compute the effects of roughness on the efficiency and resolution of a diffraction grating for use in the extreme ultraviolet.