Single-Slit Diffraction

Squeeze light through a narrow slit and it refuses to travel straight — it fans out into a bright band with fading fringes. That is diffraction.

Single-Slit DiffractionLive

light bending around edges

Controls

Presets

Slit width (µm)

Wavelength (nm)

Send light through a narrow slit and it fans out into a bright central band flanked by dimmer fringes — diffraction. The pattern follows a sinc-squared curve, with the first dark fringe where the path difference across the slit equals one wavelength. Narrower slits spread the light more, the diffraction limit that caps every lens and telescope's sharpness.

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Data Inspector

First minimum1.6°

Central width3.2°

Slit/λ36.4

Governing equation

I = I_{0} sinc^{2} β, β = \frac{π a sin θ}{λ}, a = 20 μ m, λ = 550 nm

Reading this result: Wide slit relative to the wavelength: the central peak is tight and the beam stays nearly collimated, with only faint fringes.

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How it works

Light passing a single slit spreads into a central bright maximum flanked by weaker fringes, following a sinc-squared intensity pattern. The first dark fringe appears where the path difference across the slit equals one wavelength, so narrower slits spread light more. This diffraction sets the ultimate resolution limit of every lens, microscope, and telescope.

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Frequently asked questions

Is this single-slit diffraction tool really free?▾

Yes. Single-Slit Diffraction 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.