Snell's law of refraction
Ley de la refracción (ley de Snell)
- Date
- 1621 · confidence medium
- Place
- Leiden, Netherlands
- Credited to
- Willebrord Snel van Royen (Snellius); René Descartes
- People
- 👤 René Descartes1596–1650👤 Willebrordus Snellius (Snel van Royen)1580–1626
- Field
- Communication
⚠️ Disputed: the sources disagree.
What was discovered
The ratio of the sines of the angles of incidence and refraction is constant for a given pair of media. It turns refraction into a quantitative law and enables the mathematical design of lenses.
Ibn Sahl used it in 984; Thomas Harriot knew it around 1602; Snell formulated it in 1621 without publishing it; Descartes published it in 1637 (in France it is called Descartes' law).
What it led to
- Quantitative geometrical optics and lens design
- Refractive index as a property of matter
- Fermat's principle (1662) and the speed of light in media
- Optical fibre (total internal reflection)
Built on
- Ibn Sahl's law of refraction984
- Ibn Sahl (984)
- Ptolemy's refraction tables
- Kepler's Dioptrice (1611)
Made possible
- Dispersion of white light and theory of colour1666
- Double refraction in Iceland spar (Bartholin)1669
- Light guided by a water jet (Colladon)1841-1842
- Low-loss optical fibre1966-1970
- Achromatic telescopes and microscopes
- Precision prisms