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.