The Michelson Interferometer

The Michelson Interferometer is one of the most important devices in the history of physics, playing a central role in experiments that revolutionized our understanding of light, space, and time. Today, you can explore how this device works using a powerful Michelson Interferometer Simulation Applet, built in JavaScript and running on HTML5. This interactive tool helps visualize how light interference patterns are formed and how small differences in distance can lead to profound changes in the behavior of light.

What is the Michelson Interferometer?

The Michelson Interferometer was invented by Albert A. Michelson in the late 19th century and is known for its use in the famous Michelson-Morley experiment. The device splits a beam of light into two paths, reflects the beams back, and then recombines them. As the two light beams travel different distances, they interfere with each other when they meet again, creating a pattern of bright and dark fringes.

These interference patterns depend on:

The wavelength of the light used,
The difference in the lengths of the two paths traveled by the beams, and
The angle of the mirrors in the setup.

How the Simulation Works

This Michelson Interferometer JavaScript Simulation Applet allows users to interact with a virtual interferometer, replicating real-world experiments in a controlled digital environment.

Key features of the applet include:

Light Source: A source of coherent light, which is represented by sinusoidal waves. The light moves from the source and is split by a half-silvered mirror.
Half-Silvered Mirror: This element splits the light beam into two paths, with half the light passing through and the other half reflecting at a 90-degree angle.
Mirrors: The two arms of the interferometer reflect light back using two mirrors (Mirror 1 and Mirror 2). These mirrors can be adjusted to change the distance the light travels.
Detector: The detector captures the recombined light waves, and based on the phase difference between the two beams, an interference pattern is formed.

Interactive Features

The applet offers various controls and parameters that users can adjust in real-time to see how different configurations affect the interference pattern:

Position of the mirrors: Adjusting the positions of the mirrors allows users to explore how changing the path length of one of the beams affects the resulting interference pattern.
Wave properties: The applet uses a visual representation of light as waves, making it easy to see how the phase difference between the two beams leads to constructive and destructive interference.
Real-time animation: The applet can be paused, stepped forward, or reset, allowing users to slow down and analyze specific stages of the interference process.