The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
A simple derivation is given of a formula for the intensity pattern produced by a diffusely illuminated lens-like body held between a polarizer and an analyser. The formula generalizes the results of Charman and of Pierscionek and Chan for a dielectric sphere between crossed polaroids. A dark cross is universal for all lens-like bodies whose axis of symmetry is normal to the polarizer and analyser. Intensity contours are plotted for ellipsoidal lenses.