Berlin 2005 – scientific programme

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Q: Quantenoptik und Photonik

Q 28: Poster Festkörper- und Halbleiterlaser

Q 28.9: Poster

Monday, March 7, 2005, 11:00–12:30, Poster HU

Focal Properties of Large Fresnel Lenses — •Nils Nüsse, Yasser Abdel Hadi, Patrik Erichsen und Adalbert Ding — Optisches Institut, TU Berlin

Large Fresnel lenses (maximum dimensions 0.8m x 1.05m) have been used in directly solar pumped lasers. The maximum rate of concentration depends on the angular width of the light source, the focal length, the lens errors and the misadjustment of the lens. Because of the large lens size standard optical methods could not be applied. Instead a collimator covering only a fraction of the available lens surface has been used. Data obtained in this way have been weighted and appropriately integrated. A number of Fresnel lenses of different shapes and sizes have been investigated. Particular care has been taken to measure the effect of tilting the lens from its normal plane which is perpendicular to the optical axis. The image errors caused by deviation from the ideal surface due to the manufacturing process is investigated