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Proceedings Paper

Ultrahigh-carrier synthetic diffractive elements: electromagnetic theory
Author(s): Eero Noponen
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Paper Abstract

For material processing like cutting, welding, annealing and marking CO2-lasers are often used. The in- terest in diffractive optical elements (DOEs) is increasing because of the many advantages offered by such elements. Using DOEs one can generate arbitrary beam profiles or intensity distributions in the processing plane. Novel examples of such elements are reflective polarizing beamsplitters1 and artificial index gra- tings2. The first of these elements is a metal coated wet-chemically etched v-groove grating in silicon with a pe- riod of 20 1.1.m for a wavelength of 10.6 gm. The structure was designed using an exact diffraction theory called the Differential Method3. Because of the small ratio of the period to the wavelength only three dif- fraction orders exist. For normal incidence the efficiencies of the +1st and -1st order can be attenuated from 46% down to 4% only by rotating the plane of polarization. The artificial index gratings are gratings with periods smaller than the wavelength, so that incoming light can not resolve the structure. With this type of gratings it is possible to approximate continuous phase di- stributions by binary structures. Measurements of the diffraction efficiencies of such binary deflection ele- ments have shown more than 80% in the desired +1st order.

Paper Details

Date Published: 23 July 1993
PDF: 2 pages
Proc. SPIE 1983, 16th Congress of the International Commission for Optics: Optics as a Key to High Technology, 19837O (23 July 1993); doi: 10.1117/12.2308695
Show Author Affiliations
Eero Noponen, Helsinki Univ. of Technology (Finland)

Published in SPIE Proceedings Vol. 1983:
16th Congress of the International Commission for Optics: Optics as a Key to High Technology
Gyorgy Akos; Tivadar Lippenyi; Gabor Lupkovics; Andras Podmaniczky, Editor(s)

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