Lasers - Physics for Game Programmers - page 380

Tidbit While Einstein is best known for his theories of relativity, he did not win the Nobel Prize for that
work because it was considered too speculative at the time (the fact that Einstein was a complete unknown
when he came up with relativity probably didn't help either). Einstein won the Nobel Prize in physics in 1922
for explaining a concept called the photoelectric effect.

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In 1954, Charles Townes and other researchers at Columbia University used Einstein's
theoretical groundwork to develop a device that generated a focused, concentrated beam of
microwave energy. He called it a maser , which stood for Microwave Amplification by Stimulated
Emission of Radiation. Critics ridiculed his device as an expensive waste of time, but Townes
got the last laugh when he won the 1964 Nobel Prize in physics for his work on microwave lasers.
In 1958, Townes and another researcher named Arthur Schawlow wrote a paper on how
the maser concept could be extended to create a machine that would generate a focused,
concentrated beam of visible light, and the idea of the laser was born. Similar to the Space Race,
Townes's and Schawlow's work set off a laser race to see who could build the first working
laser. Theodore Maiman at Hughes Research Laboratories won the race in 1960 by creating a
laser out of a synthetic ruby crystal that generated a red beam of light. Later that year, an Iranian
physicist named Ali Javan invented the first gas laser.
Laser development has continued ever since 1960, and there are now many types of lasers
and countless uses for them. Lasers are also cool things to add to your space battle or futuristic
combat games. Now that you know a little bit about the history of lasers, let's turn our attention
to a brief discussion of how lasers work. Before we can do that, however, we need to back up
and talk a little bit about atoms.

An Introduction to Atoms
As you probably know, everything around you—your computer, yourself, your front lawn—is
made up of tiny particles called atoms . As depicted in Figure 14-1, an atom is itself made up of
particles called protons and neutrons that are clustered together in what is called the nucleus
of the atom. The nucleus is surrounded by a cloud of particles called electrons that travel about
the nucleus in different orbits.

Electron

Nucleus

Figure 14-1. A schematic of a typical atom