paraxial approximation
1Paraxial approximation — In geometric optics, the paraxial approximation is an approximation used in ray tracing of light through an optical system (such as a lens).cite book | first=John E. | last=Greivenkamp | year=2004 | title=Field Guide to Geometrical Optics |… …
2Small-angle approximation — is a useful simplification of the laws of trigonometry which is only approximately true for finite angles, but correct in the limit as the angle approaches zero. It involves linearization of the trigonometric functions (truncation of their Taylor …
3Ray (optics) — Ray of light redirects here. For other uses, see Ray of light (disambiguation). In optics, a ray is an idealized narrow beam of light. Rays are used to model the propagation of light through an optical system, by dividing the real light field up… …
4Fourier optics — is the study of classical optics using techniques involving Fourier transforms and can be seen as an extension of the Huygens Fresnel principle. The underlying theorem that light waves can be described as made up of sinusoidal waves, in a manner… …
5Helmholtz equation — The Helmholtz equation, named for Hermann von Helmholtz, is the elliptic partial differential equation:( abla^2 + k^2) A = 0where abla^2 is the Laplacian, k is a constant, and the unknown function A=A(x, y, z) is defined on n dimensional… …
6Optics — For the book by Sir Isaac Newton, see Opticks. Optical redirects here. For the musical artist, see Optical (artist). Optics includes study of dispersion of light. Optics is the branch of …
7Negative index metamaterials — A negative index metamaterial causes light to refract, or bend, differently than in more common positive refractive index materials. Negative index metamaterials or negative index materials (NIM) are artificial structures where the refractive… …
8Gaussian beam — In optics, a Gaussian beam is a beam of electromagnetic radiation whose transverse electric field and intensity (irradiance) distributions are well approximated by Gaussian functions. Many lasers emit beams that approximate a Gaussian profile, in …
9Thin lens — In optics, a thin lens is a lens with a thickness (distance along the optical axis between the two surfaces of the lens) that is negligible compared to the focal length of the lens. Lenses whose thickness is not negligible are sometimes called… …
10Cardinal point (optics) — For other uses, see Cardinal point (disambiguation). In Gaussian optics, the cardinal points consist of three pairs of points located on the optical axis of an ideal, rotationally symmetric, focal, optical system. For ideal systems, the basic… …
