Determination of the effective focal length and cardinal points for a coaxial system of thick lenses

Abstract

In this work, an analytical method is proposed to determine the effective focal length and the six cardinal points for a system of coaxial thick lenses. The technique is different from both the Gaussian and matrix methods. We can apply it without the need to calculate the power and the principal points of the individual lenses of the system. The method is based on a proposed formula for the focal length of a whole system of coaxial thick lenses. This formula is derived in detail in the present work. The proposed method represents a simpler alternative to the Gaussian reduction method. Several numerical examples are solved in this work using the method. In these examples, we have easily calculated the effective focal length and the six cardinal points for coaxial systems of two, three, and five thick lenses in the most general case of different refractive indices.