Theory of Vergences

• Introduction
• Vergences
• Mirrors
• Interfaces
• Magnification
• Thin Lenses
• Combinations
• Aberrations
• Summary
• Examples

Introduction

Geometric optics is the study of the propagation of light in the regime in which diffraction effects (bending of light around corners) are negligible. This is the case when obstacles and openings are much larger than the wavelength of light. The focus of this section is thus the investigation of image formation by mirrors, interfaces and lenses.

There are two main approaches to geometric optics:

• Ray optics - the paths of light rays are followed and image formation determined by how the rays are bent as they interact with optical elements
• Wavefront optics - the propagation of a wavefront is followed (which is everywhere perpendicular to the light rays) and image formation determined by the convergence or divergence of the front.

The approach taken in this course is centred more around the second of these options and is called "Vergence Theory". This is somewhat different from the approach of most text books and what you may have learned in the past. Vergences provide a more powerful and elegant approach to solving problems in geometric optics and you will be expected to use this method when confronted with problems of this type.

A note on using these pages. Topics are listed on the left and should be used to navigate through the sections in the order given. Examples are provided for you to try. Answers are given but no working.

A pdf summary of these notes can be downloaded by clicking here.