Photonica simulates light the way physics does. Every ray carries its own wavelength, every lens is real glass, every photon arrives exactly when it would. Build any optical experiment you can imagine, measure it like an instrument, design optics you could manufacture, and watch light itself cross the room.
Windows 10 / 11 · RTX-class GPU · freeSnell's law, lenses, total internal reflection, polarisation, diffraction. Change one number and the physics answers back with a measurement — the same numbers your exam expects, now something you can hold.
Start with light & colour →Why a diamond throws fire, how one raindrop makes a rainbow, what a pulse of light looks like halfway across a table. Open a demo, drag a prism, and see it happen.
Your first experiment →Real glass catalogues, thin-film coatings, a damped least-squares optimiser, Monte-Carlo tolerancing with yield, Zemax import, and every measurement exported as raw JSON.
Lens design →Glass slows light down — but not every colour by the same amount. Violet crawls, red slips through, and so each colour leaves a prism at its own angle. That one fact is behind every rainbow, the fire in a diamond, and the coloured fringes on a cheap lens.
The slider runs the same dispersion formula Photonica uses for every ray: the Sellmeier equation, with the manufacturer's coefficients for two real glasses.
n²(λ) = 1 + Σ Bᵢλ² / (λ² − Cᵢ)
Nothing in Photonica is painted on. White light is dozens of wavelengths travelling together, glasses bend each one by their measured dispersion, and every surface splits the power between reflection and transmission the way Fresnel's equations say it must.
Every photon carries a real arrival time, slowed by exactly the right amount in every piece of glass it crosses. Slow the clock down billions of times and a pulse of light walks across your bench — and the screens stay dark until it has genuinely arrived.
When the geometry runs out, the wave takes over. Photonica sums Huygens wavelets for slits and apertures, sends light through diffraction gratings order by order, and carries a full polarisation state — so a quarter-wave plate really does make circular light.
Describe what a lens should do — a focal length, a spot size, zero colour error — and the optimiser bends the surfaces until it does. Then tolerancing asks the hard question: when real glass is ground slightly wrong, how many of the lenses you make will still work?
Press P and the same bench becomes a spectral path-traced photograph: caustics pooling inside the stone, beams glowing through haze, bloom around the brightest light. Same scene, same frame, same physics — drag the handle and watch the renderer change underneath it.
Both clips rendered by Photonica · drag to wipe
Photonica speaks MCP, the open protocol AI assistants use to work with tools. Ask Claude to build a telescope, measure its magnification and check it against theory — it places the lenses, reads the numbers, and verifies its own work on your screen. That's exactly how Photonica's own validation suite was run.
# connect Claude Code to Photonica claude mcp add photonica -- "…\photonica-mcp.exe" # then just ask, in plain words: "Build a Keplerian telescope with a 500 mm objective and a 50 mm eyepiece, find the spacing that collimates the output, and check the angular magnification against −f₁/f₂."
Thirty-three classic experiments — Snell, Fresnel, Brewster, the critical angle, the thick-lens equation, prism dispersion, achromats, Malus's law, wave plates, gratings, telescopes — each run through Photonica and compared to its closed-form answer. Every number and every method is published.
Photonica ray traces every photon in real time, so it needs a DirectX Raytracing 1.1 graphics card — NVIDIA RTX 20-series or newer, AMD RX 6000-series or newer, or Intel Arc. Most laptops without a dedicated GPU can't run it yet. We'd rather tell you that plainly than ship something that fakes the light to get around it.
Unzip, run, open a demo. Seventeen experiments are waiting, and the docs will take you from your first beam to your first lens design.