optical path length
Beam travel distance
Optical path length is the distance light travels through a medium, multiplied by that medium's refractive index.
It accounts for how light slows in denser materials—two paths of different physical lengths can have the same optical path length if one passes through a denser medium.
The concept is central to interference, diffraction, and lens design, where phase relationships between light waves determine outcomes.
- compensatorDevice that offsets deficiencies
- refractionWave bending between media
- interferenceUnwelcome involvement in affairs
- coherenceLogical internal consistency
- polarizationSeparation into opposing extremes
retardation · wavelength · medium · thickness · light ray · phase shift · dispersion · scattering · absorption · fiber optics · wavefront · holography · glass · cavity · crystal · collimated · laser beam · mirror