Related Experiment Video
Updated: May 13, 2026

Evanescent Field Based Photoacoustics: Optical Property Evaluation at Surfaces
Published on: July 26, 2016
Exact ray tracing formulas based on a nontrigonometric alternative to Snell's law
1High Institute of Optics Technology, El-Nozha, Heliopolis, Cairo 17361, Egypt. Hassanelagha@gmail.com
Abstract:
In this work, Fermat's principle is applied to derive a simple exact formula for refraction (reflection) in terms of the lengths of the incident and refracted rays. This formula is a nontrigonometric alternative to Snell's law and is general for all optical surfaces. It is used to derive the paraxial optics equations in a more simple and direct way than that often used in the literature. It's also applied to derive a new single, exact ray tracing formula for the nonparaxial refraction (reflection) at a single optical surface. The obtained formulas are used to develop a simple ray tracing procedure for meridional refraction through systems of spherical surfaces without the need to use any form of Snell's law. Numerical examples are provided and discussed.
More Related Videos
09:43Interfacial Molecular-level Structures of Polymers and Biomacromolecules Revealed via Sum Frequency Generation Vibrational Spectroscopy
Published on: August 13, 2019
11:30Recombination Dynamics in Thin-film Photovoltaic Materials via Time-resolved Microwave Conductivity
Published on: March 6, 2017
Related Concept Videos
The Law of Sines
Trigonometric Identities II
Trigonometric Equations
Trigonometric Identities I
Trigonometry of Right Triangles
The Law of Cosines