PPolySim OS

Polarization (Malus's Law)

Sunglasses, LCD screens, and camera filters all exploit polarization. See how each polarizer passes only the aligned component — and the famous three-filter trick.

Polarization (Malus's Law)Live

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A polarizer only passes the light-wave component aligned with its axis. Malus's law says the transmitted intensity is I₀·cos²θ, where θ is the angle between successive filters. Two crossed polarizers block everything — but slip a third at 45° between them and light reappears, a striking quantum-like result of projection.

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Data Inspector

Final intensity12.5%
Polarizers3
Crossed?no

Governing equation

Reading this result: Each filter projects the beam onto its axis, multiplying intensity by cos² of the step angle; after this chain about 13% remains.

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How it works

Light is a transverse wave, and a polarizer transmits only the component along its axis. Malus's law gives the transmitted intensity as I₀·cos²θ between successive filters. Two crossed polarizers block all light — yet inserting a third at 45° between them lets light through again, a striking demonstration of how measurement projects a wave onto a new axis.

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Frequently asked questions

Is this polarization Malus's law tool really free?
Yes. Polarization (Malus's Law) runs entirely in your browser using your device's own compute, so local use is free forever. You only pay Compute Tokens if you scale a job to the cloud.
Do I need to install anything?
No. Everything runs client-side in a modern browser — no downloads, no license, no account required to start.
Can I save or share my simulation?
Create a free account to save projects, and use a shareable embed or minted DOI to publish a live, interactive version anywhere.
How accurate are the results?
The solver uses established numerical methods, but results are for research and educational purposes and should be validated against experiment or professional review before you rely on them.