Abstract: A method of producing uniform metal mirror surfaces which are harder than e starting material. A three step machining process produces uniform metal mirror surfaces without polishing defects or lack of spatial uniformity from previous polishing methods. The surface is first machined in the normal manner for diamond turning. The second machining process requires the rake angle to be made negative to the extent of approximately 30.degree.. This machining process creates plastic deformation in the surface material. The final step requires machining material in the top rake angle of from -5.degree. to +5.degree. which provides the uniform surface of regular diamond machining. An alternate method only needs a single cut at an intermediate rake angle.

Abstract: An apparatus and method for measuring optical coupling coefficients is disclosed using the thermal expansion of a sample to reduce an externally applied tensile load of predetermined magnitude. The sample is illuminated with a known amount of incident energy. The absorption of this energy expands the sample which reduces the tension in the sample. The measurement of the tension reduction permits a direct calculation of the coupling coefficient .alpha., through use of the known parameters of a sample.