Interferometer Model - Physics Demonstrations - Interferometer Model | Physics Undergraduate Labs

Purpose

A mechanical model of a Michelson interferometer uses colored ribbons to represent light paths. Sliding one "mirror" (bench clamp) changes the ribbon alignment, showing constructive interference when colored squares match and destructive interference when red and green squares overlap.

Overhead view of interferometer model on green lecture bench, with green ribbons extending from translucent light box on ring stand, routed around bench clamps representing mirrors, with springs providing tension

Interferometer model showing the two ribbons with alternating colored squares meeting at the light box, with squares aligned to represent constructive interference

Close-up of detector area in two panels: top shows alternating red and green squares aligned (constructive interference), bottom shows red and green overlapping to create mixed colors (destructive interference)

Figure 1: Complete setup: LED light box on ring stand (beam splitter), bench clamps (mirrors), and green ribbons representing the two light paths. Springs keep the ribbons taut.

Figure 2: Ribbons aligned to show constructive interference -- the colored squares on the two ribbons match at the detector (light box).

Figure 3: Top: Constructive interference -- colored squares on the two ribbons align. Bottom: Destructive interference -- after sliding one mirror, red and green squares overlap.