Visualization of distortion using interference fringe patterns and the correction of chromatic aberration using a Fresnel zone plate with microdisplay

Abstract

This paper investigates the application of fringe analysis to the measurement of geometric lens aberration and the creation of a Fresnel zone plate based diffractive corrective for the removal of chromatic aberration. The objective of the work has been firstly to create a Fourier fringe analysis approach to analyse the minor geometric distortions found in conventional lenses. Having defined how such a system can be analysed a theoretical lens surface has been generated and the effect of the different aberrations present, analysed. A specific Fresnel zone plate corrective has then been designed and evaluated in order to minimise chromatic aberration. This has a particular application to low cost plastic optics, which cannot easily be chromatically corrected. The Fresnel zone plate shows how a diffractive corrective has been created and used to minimise the chromatic aberrations. The approach developed in this thesis demonstrates that it is now possible to remove 90% of the chromatic aberration by the use of computed diffractive corrective optics. It also investigates how a further minor diffractive corrective could reduce the lens aberration until it performs close to the diffraction limit.