IMAGING BEHAVIOUR OF A BIREFRINGENT LENS SUFFERING FROM PRIMARY COMA

In the previous two parts of this report the concept of an ʹEffective Thin Lensʹ (ETL) and of an ʹEquivalent Gaussian Lens ʹ (EGL) was developed.Along with this concept a generalized definition of ʹShape Factorʹ or ʹLoad Distribution Factorʹ had been proposed and used to implement a simple yet effective method of ʹab initio ʹ development of multi element lens system to meet specific working requirements. The present report concerns itself with indicating thepossiblility of effecting linear optimization of paraxial and first-order design. The possibility stems from the fact that the ray configurations in the object and the image spaces of the two element system being changed shall remain unaltered when the ʹLDFʹ and / or the separation are changed to modify the aberrations.