Gte Laboratories Incorporated

Donald M Koffman

Robert J Seymour

Paul Lublin

A device for efficiently coupling electromagnetic radiation in the far-infrared and submillimeter microwave regions of the electromagnetic spectrum to surface electromagnetic waves comprising a base metal substrate formed by producing periodic alternating areas thereof in which the dielectric constants differ so as to provide periodic field modulation to, in turn, enhance coupling between the surface plasmons and free photons at the proper coupling angles. The different dielectric constant areas may be formed by selective overplating or evaporating or may alternately be formed by the selective processing of a uniformly deposited material such as by annealing of an amorphous material in strips. In an alternate embodiment of the invention the periodic modulation of the dielectric constant is of the overcoat material rather than the base metal substrate.

Flat profile grating coupler

An apparatus for measuring the plating thickness of a thin gold coating on a substrate such as a sheet or thin wire is described. The gold plating thickness, which may range from one to about one hundred and fifty microinches, is measured with an X-ray analysis technique in real-time as the plating of a wire is in process. The gold plated wire is exposed to X-rays of a type and intensity selected to stimulate X-ray emission from both the gold plating and the substrate with energies which permit energy-dispersive analysis. A ratio between the X-ray energies attributable to the substrate and gold plating is employed to determine the thickness of the gold plating with a generally applicable calibration curve. The accurate and rapid gold plating thickness measurement enables the monitoring the regulation of the gold plating thickness with a feedback control in a highly accurate manner.

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Winchester, MA, United States of America

Donald M Koffman