Spectral measurement in reflection on steeply aspheric surfaces

摘要

The controls by optical mean of coatings deposited on optical components are generally made with flat witnesses. When the components are spherical or aspherical, like lenses or mirrors, the spectral response may vary because of the nonuniformity of thickness that is really linked to the deposition process. For large radius of curvature, control can be achieved even with classical spectrophotometers. However, control becomes more and more difficult when the radius of curvature decreases or when the optical device has a complex shape. Thus special devices are needed to perform this kind of measurement. ZEISS and CEA Le Ripault use spectral reflection as a mean of measurement, which enables to investigate optical coatings on curved parts. Two different devices have been implemented and used to measure the same antireflective coating deposited on an aspheric lens. In this work, we show the obtained results and we compare these results to theoretical simulation.