Physics
Laser Operation Principles
Quick fact
The first working laser, built by Theodore Maiman in 1960, used a ruby crystal and produced pulses of red light; today lasers can create beams powerful enough to cut steel or gentle enough for eye surgery.
Why this is interesting
You shine a flashlight and get a diffuse, spread-out beam. But a laser pointer shoots a pencil-thin ray that can travel miles. What makes laser light so different?