Michelson Interferometer

In this setup, an interferometer is used to measure the wavelength of laser light. The incident beam is split into two paths, recombined, and projected on a screen. When one of the path lengths is varied, the interference pattern on the screen changes. By measuring the distance that a path length must be changed in order to achieve the original interference pattern, one can determine the wavelength of the incident light.

 

How a Laser Works

Bill shows how the three key characteristics of laser light - single wavelength, narrow beam, and high intensity - are made. He explains the operation of a ruby laser - the first laser ever made - showing how electronic transitions create stimulated emission to give coherent light, and then how the ends of the ruby cavity create a narrow wavelength highly collimated beam.

Other "Engineer Guy" videos

How to Measure the Wavelength of Laser Light

Diffraction.