New device to measure the reflectivity on steeply curved surface

摘要

The controls by optical mean of coatings deposited on optical components are generally made with flat witnesses. But when the components are spherical or aspherical, like lenses or mirrors, the spectral response can 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 such as slicers for example. So to perform this kind of measurement, special devices are needed.The CEA Ripault has designed a new facility of measurements of spectral reflection. This reflectometer can be used to measure optical coating with a very high accuracy on steeply curved parts. The aim of this paper is to enhance the limits of this device by studying measurement uncertainty and giving some examples of measurement. One of our most relevant measurements is the study of an aspheric condenser having a 38 mm focal length. Furthermore, the obtained reflectivity on an angle iron will be achieved and commented. Soon, WINLIGHT SYSTEM Company will manufacture this device.