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United States Patent: Ellipsometer, John A. Woollam, Blaine D. Johs, David W. Doerr, Reed A. Christenson
United States Patent: Ellipsometer, John A. Woollam, Blaine D. Johs, David W. Doerr, Reed A. Christenson
Department of Electrical and Computer Engineering: Faculty Publications
To sense characteristics of a sample, an ellipsometer includes a pivotal diffraction grating positioned to receive white light from the analyzer without further focusing of the light after the light leaves the sample. The diffraction grating is focused on the sensor at a predetermined angle with a precision of at least plus or minus one-half degree using an alignment-sensing means positioned between the analyzer and diffraction grating. The sensor includes an aperture through which the incident beam of light is transmitted, light-sensitive areas on opposite sides of said sensor and a comparator for comparing the signal from said light-sensitive areas. …
Complex Index-Of-Refraction Measurements For Rp-1 Liquid Rocket Fuel, Dennis R. Alexander, Ramu Kaiwala, Robert D. Kubik, Scott A. Schaub
Complex Index-Of-Refraction Measurements For Rp-1 Liquid Rocket Fuel, Dennis R. Alexander, Ramu Kaiwala, Robert D. Kubik, Scott A. Schaub
Department of Electrical and Computer Engineering: Faculty Publications
Complex index-of-refraction values of RP-1 liquid rocket fuel are reported at laser wavelengths of 0.193 m (ArF excimer), 0.4765 m (argon ion), 0.488 im (argon ion), 0.5145 ji.m (argon ion), 0.532 m (Nd-YAG, frequency doubled), 0.6328 pm (He-Ne), 1 .064 im (Nd-YAG), and 10.5915 im (C02). The imaginary part of the index of refraction (k) is determined by traditional transmission methods. The real part (flr) at the specific laser lines is determined using reflectance measurements, critical-angle measurements, Mueller matrix elements, and Michelson interferometric measurements. Reflectance measurements are used to obtam n at a wavelength of 0.193 m. The critical-angle method …
Field Measurements Of Natural And Artificial Targets Using A Mid-Infrared Laser Reflectance Sensor, Ram M. Narayanan, Steven E. Green
Field Measurements Of Natural And Artificial Targets Using A Mid-Infrared Laser Reflectance Sensor, Ram M. Narayanan, Steven E. Green
Department of Electrical and Computer Engineering: Faculty Publications
tunable mid-infrared CO2 laser reflectance sensor operating in the 9-11 pm wavelength range has been developed and field-tested at the University of Nebraska. This system is capable of gathering reflectance data at various wavelengths, incidence angles and linear polarization combinations. Preliminary measurements of various natural and artificial targets such as soil, coniferous and deciduous trees, concrete and brick building material at distances of up to 100 m demonstrate the potential of this system to characterize the mid-infrared reflectance of terrain features for remote sensing applications. Field-acquired data compare well with data on similar materials measured in the laboratory under …