Lesson 8 – Optical Sources

Light may be created in many ways. Early optical sources simply heated material until it glowed a broad rainbow of light. These are incandescent and blackbody sources. Exciting an isolated plasma of atoms and molecules using electricity causes natural emission of very specific spectral lines, colors that are characteristic of the excited chemicals. The semiconductor industry provides engineered optical sources that emit narrow bands of colors from light-emitting diodes (LEDs). The ultimate engineered optical source is the laser, which produces a monochromatic (single color), directional, and coherent beam of light.