About Lightsmith Materials

Lightsmith Materials is an open database of optical constants (refractive index n, extinction coefficient k and permittivity ε) in which every dataset is tied to its source publication. It is the materials service of Lightsmith, the open photonics suite.

Where the data come from

The content is the complete refractiveindex.info database by M. N. Polyanskiy, released into the public domain (CC0 1.0) and imported unchanged at a pinned commit of its repository (c5c2f188e8, imported 2026-11-02). Shelves, books, pages and their order are kept, so each page here corresponds to one page there. Lightsmith Materials is not affiliated with refractiveindex.info. Community contributions are reviewed by moderators before they appear.

How to cite

Cite the reference listed on the dataset's page, and the database:

M. N. Polyanskiy, Sci. Data 11, 94 (2024), doi:10.1038/s41597-023-02898-2. doi:10.1038/s41597-023-02898-2

Conventions

• Wavelengths are vacuum wavelengths. Pages show µm, as the source does; the API uses nm.
• Time dependence exp(−iωt), so absorbing media have k > 0 and Im ε > 0, the same as the Lightsmith library.
• Tables are interpolated linearly and never extrapolated; formulas are evaluated exactly.
• Data are shown as published. Problems found in the source data (k < 0, for example) are flagged on the page.

Numbers in your code

Every dataset page has copy-paste Python for the Lightsmith library. The REST API serves the same data as JSON, CSV, tab-separated text and YAML: see the interactive API reference.

Statistics

2,248 materials, 3,478 datasets and 671 references, 514 of them with a DOI.

Licences

The site and API code are MIT-licensed. Each dataset carries its own data licence (the imported data are CC0 1.0).