TABLE OF CONTENTS This chapter is intended to provide the reader with the tools necessary to determine the location, size, and orientation of the image formed by an optical system. These tools are the basic paraxial equations which cover the relationships involved. The word "paraxial" is more or less synonymous with "first-order" and "gaussian"; for our purposes it means that the equations describe the image-forming properties of a perfect optical system. You can depend on well-corrected optical systems to closely follow the paraxial laws.
In this book we make use of certain assumptions and conventions which will simplify matters considerably. Some assumptions will eliminate a very small minority [*] of applications from consideration; this loss will, for most of us, be more than compensated for by a large gain in simplicity and feasibility.
All surfaces are figures of rotation having a common axis of symmetry, which is called the optical axis.
All lens elements, objects, and images are immersed in air with an index of refraction n of unity.
In the paraxial region Snell's law of refraction ( n sin I = n ? sin I ?) becomes simply ni = n ? i ?, where i and i ? are the angles between the ray and the normal to the surface which separates two media whose indices of refraction are n and n ?.
Light rays...
