Paper
12 December 1989 Chromatic Dispersion Compensation In A Fresnel Lens By Means Of A Diffraction Grating
Kenneth C. Johnson
Author Affiliations +
Abstract
A Fresnel lens's imaging performance can be seriously impaired by chromatic dispersion which typically doubles the diameter of the focused sun image in a solar concentrator. This problem can be alleviated by means of a molded diffraction grating whose diffraction-induced dispersion offsets and substantially cancels the lens's intrinsic refractive index dispersion. The grating lines would comprise a second tier of small-scale, Fresnel-type facets superimposed on the lens facets, with a typical grating facet height of about 40 microinches and a facet width ranging from about 1 milliinch at the edge of the lens to around 5 or 10 milliinches near the center. In its primary intended application the grating would function in a core daylighting system to improve the optical performance of a collector which focuses direct sunlight into fiber optic couplers. For this application chromatic dispersion would be reduced by an order of magnitude with only a 2% loss in optical efficiency.
© (1989) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Kenneth C. Johnson "Chromatic Dispersion Compensation In A Fresnel Lens By Means Of A Diffraction Grating", Proc. SPIE 1149, Optical Materials Technology for Energy Efficiency and Solar Energy Conversion VIII, (12 December 1989); https://doi.org/10.1117/12.962179
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CITATIONS
Cited by 6 patents.
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KEYWORDS
Diffraction gratings

Energy efficiency

Dispersion

Solar energy

Fresnel lenses

Photovoltaics

Solar concentrators

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