Visible optical beats at the hertz level

TL;DR

This paper introduces a portable Mach-Zehnder interferometer that visually demonstrates optical beats at the hertz level, serving as an educational tool for illustrating interferometry and laser modulation concepts.

Contribution

It presents a simple, accessible setup for visualizing low-frequency optical beats, bridging the gap between audible and optical interference demonstrations.

Findings

Produces visible beating interference patterns at hertz frequencies

Uses common laser physics components for easy assembly

Suitable for advanced laboratory teaching and demonstrations

Abstract

We present a lecture demonstration which produces a visible, beating interference pattern that is the optical analog of demonstrations which produce audible, beating sound-wave interference. The setup is a compact, portable Mach-Zehnder interferometer made of optical components commonly found in laser physics labs. This apparatus may also be built and used in advanced laboratory courses to illustrate concepts in interferometry and laser light modulation.