Schaums Outline of Optics
As is the case of many of the Schaums books, this is an incredibly useful reference book with chapters that can be looked into as required. For the price, it is thoroughly recommend owning this if you are studying optics or photonics / lasers. Quite mathematically intensive in some places, it gives great examples and worked through problems which could be adapted for your own work.
Photonics: Rules of Thumb
Each section starts off with the useful or “required” equations without pages of derivations. After the equations are given, there is then a discussion describing the terms and what the equation is used for. A useful book as you don’t always have time to read through heavy derivations, and just having the information you need straight away is a great time saver.
Laser Material Processing
This is an excellent book on Lasers and their applications. Mathematics in this book are present and generally simplistic and the diagrams are clear and easy to follow.