Fabrication and characterization of layered spherical infrared filter particles

The ability to deposit layers of optical material on to micro-spherical particle substrates yields interesting and optimal electromagnetic mass extinction and other Mie theory scattering spectrum properties. Microsphere particle infrared filters, for use within the near-infrared/short-wavelength infrared (NIR/SWIR, λ=1µm to 3µm) and long-wavelength infrared (LWIR, λ=8µm to 12µm) spectral bands can be engineered by selecting materials with specific geometries and wavelength dependent complex refractive indices that tailor to desired mass extinction spectrum characteristics. ☐ Infrared filters that are lightweight and possess isotropic geometries, namely microspheres, are extremely valuable in many atmospheric science related applications. However, the applications certainly do not stop there; some other examples include use in diffusive blended inks and paints. Computationally, it has been shown that engineered particles possess superior wavelength specific mass extinction properties than many other infrared particle filters in existence currently. ☐ In this thesis, the method of fabrication of such layered microsphere particles will be detailed. Through renovation and modification of a radio frequency magnetron sputtering system layers were able to be deposited on to micro-spherical substrates with measurable layer thicknesses. Results of characterization will also be shown. Furthermore, future directions and other applications will also be discussed.