Abstract

When designing an imaging optical system with an extended imaging region or volume, either an appreciable number of refracting or reflecting surfaces is needed or a limited number of aspherical surfaces. The introduction of a single aspherical surface is sufficient to assure axial stigmatism. Interesting examples of the attainment of axial stigmatism with a single asphere are found in the class of surfaces of revolution which show a conical section when the surface is cut through the optical axis; the most well-known example is the paraboloid generating a perfect image of an infinitely distant object in its focus. In general, stigmatic imaging can be obtained by aspherizing one reflecting or refracting surface in an optical system [1]; other ’correcting’ means like a diffractive surface (DOE) or an inhomogeneous medium may equally serve to obtain the stigmatic imaging.

© 1998 Optical Society of America