chapter 9, Optical Materials and Coatings

Excerpt

9.1 Introduction

This chapter will be devoted primarily to discussing a variety of materials that are used in the design and manufacture of optical components. The most common of these is optical glass, in its many forms. Other materials, such as plastic and fused silica, are sometimes substituted for optical glass in order to take advantage of their special characteristics. Optical coatings are added to components to enhance their optical performance. Antireflection coatings will improve the light transmission of a lens. Single- and multiple-layer antireflection coatings will be covered. Materials for use in infrared systems are unusual in several respects. The basic characteristics of the most commonly used IR materials will also be presented.

All these topics will be covered in an introductory fashion, with the intent to provide the reader with a level of knowledge that will permit you, as the optical designer, to generate basic specifications and discuss requirements with specialists in these fields.

9.2 Optical Glass

The material we refer to as optical glass differs from the more common glasses in that its make up and ultimate performance characteristics are precisely controlled during all stages of the manufacturing process. This permits the optical designer to generate a design configuration based on published catalog data that, when manufactured, will perform exactly as indicated by the design data.

There are several reliable, established sources for optical glass throughout the world. Primary sources manufacture a complete variety of precision optical glasses from basic raw materials. Other glass suppliers act as processors, taking bulk supplies of glass from the original manufacturers and modifying the size and shape of starting glass blanks, and precisely controlling the characteristics of the glass during this process.