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Proceedings Paper

LIL filtering lenses back focus length absolute measurement
Author(s): Jean-Christophe Poncetta; Vincent Beau; Genevieve Chabassier; Jacques F. Rodolfo; Remi Bourgois; C. Hurst; Francois Houbre
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Paper Abstract

As part of the LIL (Ligne d'Integration Laser) and LMJ (Laser Megajoule) projects, CEA/CESTA and SAGEM company have carried out an accurate metrology of the back focus length of filtering lenses. These measurements should enable us to make up for a lack of focus adjustment on the laser and to correctly position these lenses. Three different lenses have been characterized: • Lenses L1 and L2 with a back focus length of 10 m (aperture of F/16). Uncertainty is estimated at ±1,3 mm. • Lens L3 with a back focus length of 26 m (aperture of F/43). Uncertainty is estimated at ±5,3 mm. To achieve these measurements, 4 methods have been used: (1) Measurement of the curvature radius of each side on a Coordinate Measuring Machine and index homogeneity characterization before polishing. (2) Interferometric measurement with a reference spherical mirror. (3) Interferometric measurement using a lens side as a reference spherical mirror with a flat mirror. (4) Interferometric measurement by closing the cavity at the top of the lens back side. Uncertainty calculation has been done for each method.

Paper Details

Date Published: 19 November 2003
PDF: 2 pages
Proc. SPIE 4829, 19th Congress of the International Commission for Optics: Optics for the Quality of Life, (19 November 2003); doi: 10.1117/12.530105
Show Author Affiliations
Jean-Christophe Poncetta, Commissariat a l'Energie Atomique (France)
Vincent Beau, Commissariat a l'Energie Atomique (France)
Genevieve Chabassier, Commissariat a l'Energie Atomique (France)
Jacques F. Rodolfo, REOSC (France)
Remi Bourgois, REOSC (France)
C. Hurst, REOSC (France)
Francois Houbre, REOSC (France)

Published in SPIE Proceedings Vol. 4829:
19th Congress of the International Commission for Optics: Optics for the Quality of Life

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