Optical components

thumb|A Burning glass|burning apparatus consisting of two [[biconvex lens]]

transparent optical element with flat, polished surfaces that refract light

optical system diffracting light into several components based on interference

optics and photography

thumb|right|A polarizing filter cuts down the reflections (top) and makes it possible to see a photographer through the glass at roughly Brewster's angle although reflections off the back window of the car are not cut because they are less-strongly polarized, according to the [[Fresnel equations.]]

A retroreflector (sometimes called a retroflector or cataphote) is a device or surface that reflects light or other radiation back to its source with minimum scattering. This works at a wide range of angle of incidence, unlike a planar mirror, which does this only if the mirror is exactly perpendicular to the wave front, having a zero angle of incidence. Being directed, the retroflector's reflection is brighter than that of a diffuse reflector. Corner reflectors and cat's eye reflectors are the most used kinds.

optical device that splits a beam of light in two, crucial part of most interferometers

[[Image:Waveplate.png|thumb|300px|

device that integrates multiple (at least two) photonic functions

thumb|The reticle of a PSO-1 scope mounted on a Russian SVD [[designated marksman rifle]] thumb|A comparison of different reticles used in telescopic sights thumb|Measurement graticule in an optical microscope thumb|Reticle of Bell & Howell Pocket Comparator thumb|Reticle accessory (PD-8) used in sniper rifles A reticle or reticule, also known as a graticule or crosshair, is a pattern of fine lines or markings built into the eyepiece of an optical device such as a telescopic sight, spotting scope, theodolite, optical microscope or the screen of an oscilloscope, to provide measurement reference

optical component which transmits light in one way only

device used to focus light using diffraction

structure that guides electromagnetic waves in the optical spectrum

thumb|upright=1.5|Simplified working principle of grisms

structure formed by reflecting faces

used in optical projection

material that diffuses or scatters light, producing soft light

A nuller is an optical instrument, e.g., a beam combiner for nulling interferometry, used to block or cancel out a strong source so that fainter signals near that source can be observed. This is typically useful to detect off-axis exoplanet or exozodiacal dust by interferometrically nulling out the on-axis parent star.

accessory for astronomical and geodetic telescopes for observing zenith nearby stars

optical equivalent of a conventional circulator

glass with roughened surface

device used to reduce the power level of an optical signal