A spectrophotometric method for determining complex index

Thesis (M.S.)--University of Rochester. College of Engineering and Applied Science. Institute of Optics, 1958. This thesis was digitized by the Institute of Optics in 2014 and was determined to have lapsed into the public domain. If you are the author and have questions about the digitization of your work, please contact Kari Brick, Graduate Program Coordinator for the Institute of Optics, at kbrick@ur.rochester.edu. Other contact information for the Institute is available at http://www.optics.rochester.eduThis work introduces the use of a spectrophotometric method for determining the optical constants of metals for determining the optical constants of metals which compares favorably with most polarized light techniques as to the attainable accuracy. Briefly, the method involves the use of an opaque metal, an auxiliary dielectric film, and normal incidence spectrophotometric measurements. The method is applied to the determination of the complex refractive index of evaporated iron in the infrared from 1 micron to 5.25 microns. It is found that the rate of evaporation of iron is not an important factor in the optical properties if good pressures are maintained during the evaporation. However, the pressure at which the evaporation occurs is found to have a strong effect of the resulting properties. The measured reflectances and transmittances of iron for several thicknesses are reported. A subjective discussion of the properties of evaporated zinc sulfide is undertaken, with special emphasis on evaporating conditions. It is found possible to evaporate at a considerably higher rate than is believed feasible by other worker. The refractive index and absorption of evaporated germanium in the wavelength range from 1.6 microns to 10.5 microns as measured by the author is reported. A few comments are included on the optical properties of evaporated tungsten oxide. The most interesting property of this material is perhaps the sensitivity of the refractive index to the pressure at which it is formed. The index is found to vary from 1.4 for evaporations made at 60 microns Hg to 2.04 for evaporations made at 5 x 10⁻⁵mm. Hg