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Optical Engineering

Diffractive microlenses with antireflection coatings fabricated by thin film deposition
Author(s): Edgar Pawlowski; Herbert Engel; Margit Ferstl; Walther Fuerst; Berndt Kuhlow
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Paper Abstract

Two-dimensional arrays of Fresnel zone microlenses were fabricated and coated with antireflection layers by an ion beam sputter deposition technique. The reflection of these lenses was analyzed on the basis of an angular spectrum approach for different substrate materials. A minimum reflectivity as low as 2 x 10-4 was realized by means of in situ controlled multilayers of TiO2 and SiO2. The lenses have a circular aperture of 2 mm and different focal lengths for the wavelengths of 1.52 and 0.63 μm, respectively. The kinoform profile in each zone of the Fresnel zone lenses was approximated by an eight-level profile. Such stepped profiles were realized with several masks written with an electron beam and transferred by photolithographic technology. Our measurements reveal that the spot sizes of the fabricated microlenses are close to the diffraction-limited values, and the highest measured diffraction efficiencies for the eight-level structures are greater than 80%.

Paper Details

Date Published: 1 February 1994
PDF: 6 pages
Opt. Eng. 33(2) doi: 10.1117/12.153180
Published in: Optical Engineering Volume 33, Issue 2
Show Author Affiliations
Edgar Pawlowski, Heinrich-Hertz-Institut (Germany)
Herbert Engel, Heinrich-Hertz-Institut (Germany)
Margit Ferstl, Heinrich-Hertz-Institut (Germany)
Walther Fuerst, Heinrich-Hertz-Institut (Germany)
Berndt Kuhlow, Heinrich-Hertz-Institut (Germany)

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