Optics
4 terms
Fermat's Principle
Optics
s (or m)
The fundamental principle stating that light traveling between two points follows the path that requires the stationary (usually minimum) optical path time.
Optical Path Length L = ∫ n(s) ds = extremum
Fraunhofer Diffraction
Optics
m
Far-field wave diffraction where both incident and observed wavefronts are planar, achieved using lenses or large distances.
a sin θ = m λ
Fraunhofer Lines
Optics
nm
A set of dark absorption lines in the solar spectrum caused by chemical element absorption in the Sun's outer atmosphere.
E = h ν = E_upper - E_lower
Fresnel Diffraction
Optics
N/A
Near-field wave diffraction where source or observation screen is close to the diffracting aperture, requiring spherical wavefront curvature analysis.
Fresnel Number F = a² / (λ L) ≳ 1