Effects of striae in optical glass on optical systems – first results
Hochschule Pforzheim, Tiefenbronner Str. 65, D-75175 Pforzheim, Germany; 2 Hochschule Darmstadt, Schöfferstr. 3, D-64295 Darmstadt, Germany; 3 SCHOTT AG, Advanced Optics, Hattenbergstr. 10, D-55122 Mainz, Germany; 4 Friedrich-Schiller-Universität Jena, Institute of Applied Physics, 07745 Jena, Germany
steffen.reichel@hs-pforzheim.de
Abstract
A striae is a small local change in the refractive index of optical glass (structure width ~ 0.1 – 1.0 mm, n < 10-3) leading to a wavefront deviation. Here, the effect of striae in optical systems will be studied. Striae will be modelled as a surface modification resulting in a wavefront deviation. This thin lens approximation will be justified. A single stria will be simulated for a camera lens, a digital projector, and a binocular. A worst case simulation will be done for estimating the effect of striae on the optical performance for these different systems. The striae will be put on different critical surfaces and also on different locations on the surface for all optical systems. Besides a single striae also multiple striae are modelled and examined. The amplitude of the striae is modified according to the definitions in the standard ISO 12123 and the structural width is modified from 0.1 mm up to 1.0 mm. This difficult simulation task brought the software Zemax sometimes to its limits. The issues of a careful modelling of the perturbations are discussed.