Determination of the paraxial focal length of strong focusing lenses using Zernike polynomials in simulation and measurement

In the design of a lens the most important parameter is the paraxial focal length. Though, most focal length measurement methods are not measuring the paraxial focal length, but a focal length influenced by aberrations. We have developed a method to determine the paraxial focal length of strong focusing lenses using experimental ray tracing in a 2D cross section measurement. The method developed by us gives a much higher accuracy in measuring the paraxial focal length than the compared methods according to the German Institute for Standardization and Neal et al.. It shows an accuracy of up to 0.15% in measurement.