OpticalSetup

A 2D optical workbench in the browser: draw a setup, watch the light being traced through it live, read what the detectors receive, and export a paper-ready figure or a self-contained share link.

➡ Try it in your browser: https://opticalsetup.com/sketch/ (mirror: https://lucagenchi.github.io/opticalsetup/sketch/)

No account, no installation and no server-side storage: the app is plain static files that run entirely in your browser.

What you can do

• Build a setup. Search or browse the element palette and place components on a virtual optical table seen from above: sources (lasers, LEDs, lamps, pulsed and supercontinuum lasers), mirrors, lenses and objectives, filters, dichroics and beamsplitters, polarization optics, gratings and prisms, modulators, nonlinear crystals and parametric sources, fibers, samples, detectors, and free-form glass.
• See the light. Beams are ray-traced live as you edit: mirrors fold, lenses focus, dichroics split by wavelength, gratings and prisms disperse, samples fluoresce, fibers re-emit. Beam colour follows wavelength.
• Tune components. Select an element to drag, rotate, resize or adjust it on the canvas, or set exact values (focal length, wavelength, transmission band, angle…) in the inspector.
• Measure. Photodiodes, PMTs, cameras, spectrometers and beam probes report power, spectrum, polarization, beam profile and pulse timing at their position; a linked display shows a reading directly on the canvas.
• Explore interference. Sized CW, pulsed and supercontinuum sources can interfere through supported ideal interferometer optics. Broadband output power and spectra follow the path difference; recombined temporal waveforms are outside this model.
• Animate pulses. Pulsed sources play wavelength-coloured packets along the traced path, with timing from the optical path length and duration that follows the dispersion accumulated along the way.
• Learn from examples. The Examples menu opens ready-made setups — imaging systems (telescopes, microscopes, cameras), interferometers, laser cavities, OPOs and ultrashort-pulse systems — each with an explanatory page.
• Export and share. Save and load setups as .json; export figures as SVG or PNG, or animations as GIF; share a setup as a link (and QR code) that carries the whole scene.
• Work offline. Install it as an app on desktop or mobile; after the first visit it keeps working without a network, and your sketch autosaves in the browser.

How it works

1. Scene. A setup is a list of components, each with a position, rotation and parameters. A component registry defines every element: its drawing, its optical surfaces, its defaults and whether it is simulated, needs setup, or is a diagram-only annotation (arrows and labels never touch the light).
2. Tracing. Each source emits rays that are propagated surface by surface in 2D. At each hit the element decides what happens — reflection, refraction on the true curved surface, wavelength-dependent splitting or diffraction, polarization changes (Stokes), absorption or conversion — and the ray carries on with its wavelength, power weight, polarization and accumulated optical path and dispersion.
3. Readouts. Detectors collect the light that reaches their surface and turn it into readings using their own model; these are recomputed every time the scene changes.
4. Rendering and export. The canvas draws the components and traced beams; the same geometry produces the SVG, PNG and GIF exports, so a figure matches what you saw.

Scope

OpticalSetup computes what it shows, within stated limits: rays come from the surfaces on the canvas, dispersion from catalogue glass data, and readings from the traced light. It is built for designing, understanding and communicating setups — not as a replacement for optical design software. It works in 2D and does not do tolerancing, lens optimization or full diffraction and wave propagation; power readings are relative unless the sources' powers are set. Each component's limits are listed on its wiki page, and the full per-model notes are in docs/model-details.md.

Selected quantitative models are checked against independent Python reference implementations; see docs/validation.md and docs/adding-physics.md.

Beyond the editor

• Wiki — one page per component: the real-world physics and how the app simplifies it.
• Example setups — background, model limits and references for each built-in example.
• Calculators — interactive pages for individual physical models, running workbench models and frequency relations: material dispersion (GVD, TOD and pulse stretching), nonlinear frequency conversion (SHG, THG, SFG, DFG, OPO), coherent Raman scattering (CARS, CSRS, resolution, and the probed window on measured reference spectra), one-photon fluorescence (a CW laser on measured fluorescent-protein spectra from FPbase, stacked emission filters, typical detector QE, crosstalk and saturation) and parametric amplification.
• Community — setups shared by users; accepted submissions get their own page and appear in the app's community menu.

These pages are generated from content files; see the site structure notes.

Run locally

npm ci                # once: dev dependencies (KaTeX) for the page generators
node serve.mjs        # landing page: http://localhost:5182
                       # app: http://localhost:5182/sketch/
npm test               # runs the regression suite

(Any static file server works; ES modules require http(s), not file://.)

The public site is published by release, not by merge, and each released app stays available at /vMAJOR.MINOR/sketch/ so that shared links keep opening the app that made them; see docs/release-policy.md.

Feedback and contributing

To contribute a setup, press Propose in the toolbar: it submits the current sketch with your description for review, and accepted setups are published in the Community section. The canvas autosaves in your own browser, so you can't break anything for anyone else. For everything else — bug reports, wiki corrections, examples and code — see CONTRIBUTING.md; maintainers publishing a community submission should follow docs/community-setup-review.md. The sanitized Codex conversations behind the major development passes are in the work-trace index.

License

OpticalSetup is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. It is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See LICENSE for the full text.

Copyright (C) 2026 Luca Genchi and the OpticalSetup contributors.

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