Optics and Photonics: What is it?

[DaVinci]

I have a pretty good idea on the basics of optics and photonics but I am hoping that someone here has some indepth knowledge about the particulars of these fields.

What is the core of these fields? Meaning, if you had to descibe the optics field in one paragraph, same with photonics, what would you say about it to really portray what it is as a whole?

[Laser Jock]

Definitions may vary, but I would define the field of optics as the entire branch of physics and engineering that investigates and exploits the properties of light. Optics is a sub-field of physics, but it also includes optical engineering that cannot be classified under pure physics. It would cover everything from classical optics (lenses, mirrors, etc.) to theoretical quantum optics. As a result, I would classify photonics as a sub-field of optics just like electronics is a sub-field of engineering.

Here is quote from the preface in "Fundamentals of Photonics" by Saleh and Teich:

In recent years, the term photonics has come into use. This term, which was coined in analogy with electronics, reflects the growing tie between optics and electronics forged by the increasing role that semiconductor materials and devices play in optical systems.

I would also say that photonics is a more engineering oriented approach to optics. It includes fiber optics, optical processing, and the like.