Optical Coatings from Design through Manufacture

A logical approach to optical coatings, their design, manufacture, properties and application. Optical coatings are traditionally thought to be rather mysterious with the unexpected the norm and success dependent on skill and experience and a certain degree of good fortune. However there are excellent reasons for even the extremely bizarre behavior of coatings and it is an understanding of these reasons that is the key to real, effective, expertise in the subject. Understanding is the emphasis throughout this course, which covers all aspects of coatings from design through manufacture.

The course is a mixture of formal lectures and hands-on tutorials with a computer for each student. The objective is the presentation of a logical unified treatment of the subject with emphasis throughout on understanding and reasoning.

There are no prerequisites although a familiarity with high-school mathematics and/or science would be useful.

Course Description

Calculation of the optical properties of a given thin-film coating is straightforward. Designing for desired optical properties is rather more difficult. Reverse engineering that attempts to identify the errors responsible for manufacturing failures is similar to design but requires a much greater level of understanding. Computers are absolutely necessary in these tasks and so hands- on instruction in computer-aided design is an important aspect of the course. But other supporting techniques that help in understanding the output of the computer and include powerful, back-of-the-envelope methods are even more important and are covered in detail. Optimization and synthesis, included in the course, are impressive methods but in no way replacements for understanding.

Optical film behavior is quite different from that of similar bulk material and it is film microstructure that is largely responsible. Film growth, microstructure, crystallinity, interaction with the environment and, especially, failure modes are important course topics. Much of this can be included in a simple yet comprehensive model of film growth.

A further course objective is an appreciation of deposition processes, the effects of deposition errors, and of tolerances.

The tutorials allow individual students to go deeper into aspects of particular interest to them, and they may include investigations of their own specific problems. For the duration of the course each student has the sole use of a computer, which, for our convenience, carries the Essential Macleod package but it is not necessary to possess this software to benefit from the course.

The lecture notes are extensive and have been specially written. Attending the course is the only way in which they may be obtained.

Day 1		Fundamentals, Dielectrics, metals, semiconductors, Coating types, Thin film calculations, Visualization and analysis tools

Day 2		More tools, Polarization, Color, Design of specific coatings,

Day 3		Optimization and synthesis, Thin film deposition processes, Optical monitoring and tolerances

Day 4		Microstructure, crystallinity and film growth, Thin film properties and their relation to microstructure, Moisture adsorption,

Day 5		Adhesion, stress abrasion resistance, thermal cycling, Reverse engineering,

Day 1 To Day 5		Problem solving, Hands-on tutorial sessions.