Part I
Getting Up to Speed on Optics Fundamentals
In this part . . .
Optics is the study of light, so Part I is designed to provide you with the basic properties of light and some of the mathematics you need in order to use the various equations in the rest of the book. I explain the basic wave properties and particle properties of light, the experiments that caused the change from one model to the other, and the remarkable discovery of photons. You also find out about the three ways to produce light and the three basic processes that you can use to make light go where you want it to go. All of optics is based on the properties and models presented in this part, so they form the basis for all the other phenomena and devices you discover in this book.
Chapter 1
Introducing Optics, the Science of Light
In This Chapter
Uncovering the basic properties of light Getting a glimpse of optics applications Light is probably one of those things that you take for granted, kind of like gravity. You don’t know what it is or where it comes from, but it’s always there when you need it. Your sight depends on light, and the information you get about your environment comes from information carried by the light that enters your eye.
Humans have spent centuries studying light, yet it remains something of a mystery. We do know many properties of light and how to use them to our benefit, but we don’t yet know everything. Therefore, optics is the continuing study of light, from how you make it to what it is and what you can do with it. In fact, optics consists of three fields: geometrical optics, physical optics, and quantum optics. As we learn more about light, we find new ways to use it to improve our lives. This chapter shines a little, well, light on light.
Illuminating the Properties of Light
Because of an accidental mathematical discovery, light is called an electromagnetic wave, a distinction indicating that light waves are made up of electric and magnetic fields. You’re probably used to thinking of light as the stuff your eyes can detect. For many people who work with light on a regular basis, however, the term light applies to all electromagnetic radiation, anything from ultra-low frequencies to radio frequencies to gamma rays.
Light has both wave and particle properties (as I discuss in the chapters in Part I), but you can’t see both at the same time. Regardless of the properties, light is produced by atoms and accelerating charges. You can choose from many different arrangements to produce light with the desired wavelength or frequency (basically, the color that you want). Optics covers every light source from light bulbs to radio transmissions.
You have three ways to manipulate where light goes (that is, to make light do what you want): reflection, refraction, and diffraction, which I introduce in the following sections. You can use some basic equations to calculate the result of light undergoing all these processes. Optics then goes farther to investigate ways to find practical uses of these phenomena, including forming an image and sending digital data down a fiber.
Creating images with the particle property of light
You most commonly see the particle property of light when you’re working with geometrical optics, or making images (see Part II). In this theory, the particles of light follow straight-line paths from the source to the next surface. This idea leads to the simplest type of imaging: shadows. Shadows don’t give you a lot of information, but you can still tell the shape of the object as well as where the light source is.
Two important concepts in geometrical optics are reflection and refraction. Reflection describes light bouncing off a surface. Refraction deals with the bending of the path of the light as the light goes from one material to another. You can use these processes to create and modify images, and knowledge of these effects can also help you deal with factors called aberrations, which cause an image to be blurry. You can also use the lenses and mirrors that work with refraction and reflection to eliminate the washed-out effect you sometimes get when creating an image; if you have too much light, all the images created wash each other out, so all you see is light.
Harnessing interf...
