The concept of a laser was first invented by Charles Townes and Arthur Schawlow in 1958 while working at Bell Labs, but first laser was not built until 1960 by Theodore Maiman. Since that time many improvements and innovations have occurred, and today there are thousands of lasers being used in medical, industrial, telecommunication and defense applications.
The word Laser is actually an acronym
- L is for Light
- A is for Amplification
- S is for Stimulated
- E is for Emission
- R is for Radiation
A laser differs from other light sources (flame, flashlight, lightbulb or LED) in that the light it produces is very directional or coherent. This allows the light to project in a beam or narrow cylinder instead of randomly illuminating in all directions simultaneously. Lasers also emit light over small ranges or at single wavelengths. The wavelengths can be attributed to colors of the light and are usually based on the laser type. Examples of colors for lasers include Helium Neon (HeNe) which has a red beam around 632 nm or YAG laser which emits at 1064 nm and is invisible to the naked eye (infrared) and CO2 lasers that emit at 10,600 nm which is very deep in the infrared. The Argon Ion laser is a tuneable laser that can be adjusted to produce several different colors including violet (458 nm), blue (488 nm) and green (514 nm).