Optics
The nature of light, reflection, refraction, polarisation, mirrors, lenses, and optical applications — from electromagnetic waves to medical imaging.
University of Szeged · Department of Medical Physics & Informatics · v2.5
Introduction — The Nature of Light
Light has a dual nature: it behaves as a transverse electromagnetic wave (Maxwell, 1873) and also as a stream of photons — discrete energy packets (Einstein). Electromagnetic waves need no medium to propagate. Visible light spans wavelengths from 390 nm (violet) to 750 nm (red).
The Electromagnetic Spectrum
Geometrical Optics & the Ray Model
In geometrical optics, diffraction and interference are negligible. Light travels in straight lines (rays) through uniform media and changes direction at boundaries. Rays are perpendicular to wavefronts. This approximation works well when objects are much larger than the wavelength of light.