Photonics Dictionary

A material used as a protective layer on an aluminized or silvered mirror. It is evaporated on the mirror as a thin layer, and after exposure to the air the monoxide tends to become silicon dioxide...

A laser pumped by solar radiation focused by mirrors.

A solid-state laser is a type of laser that uses a solid gain medium (as opposed to a liquid or gas) to produce coherent light. The term "solid-state" refers to the fact that the active medium, where...

A spatial light modulator (SLM) is an optical device that modulates or manipulates the amplitude, phase, or polarization of light in two dimensions, typically in the form of an array. SLMs are...

An optical instrument for forming the spectrum of a light source and recording it on a film. The dispersing medium may be a prism or a diffraction grating. A concave grating requires no other means...

Pertaining to the manner in which light is reflected, as by a mirror or speculum.

Spherical aberration is an optical aberration that occurs when light rays passing through a lens or curved optical surface do not converge or diverge to a single focal point. Instead of focusing to a...

An instrument for measuring the radius of curvature of a spherical lens or mirror surface. It may consist of a ring resting on the surface, with a micrometer plunger in the middle of the ring to...

A laser resonator in which a mode oscillating between the mirrors will converge upon the laser's longitudinal axis.

A method of polishing an aspheric surface by mechanically distorting the optic while polishing the surface to a perfect sphere. When the stress is released, the substrate assumes the desired aspheric...

A pulsed interferometer that permits the continuous quantitative mapping of the surface deformation of an adaptive optical element (e.g., a deformable mirror) and provides the capability for...

The distance between two focal lines in an astigmatic image produced by a lens or mirror.

Controlled beam technology that introduces beams of sunlight through holes in a roof that are relayed throughout the building by a series of mirrors and lenses. Ideally, cool lighting is obtained by...

A semiconductor laser diode that emits light perpendicular to the active region. The output radiation is taken through the surface as opposed to through a cleaved mirror.

An instrument used to measure the luminance (brightness) of a distant object. The object is viewed through a small telescope, and a mirror in the focal plane reflects an internal illuminated surface...

An afocal optical device made up of lenses or mirrors, usually with a magnification greater than unity, that renders distant objects more distinct, by enlarging their images on the retina.

A telescope lens is a primary optical component of a telescope system that gathers and focuses light to form an image. It is typically a curved, transparent piece of glass or other optical material...

A terahertz spectrometer is a scientific instrument used to measure and analyze the properties of materials in the terahertz frequency range, typically spanning from about 0.1 to 10 terahertz (THz),...

A thin layer of a substance deposited on an insulating base in a vacuum by a microelectronic process. Thin films are most commonly used for antireflection, achromatic beamsplitters, color filters,...

Thin-film coatings are layers of material applied to the surface of an object or substrate, typically to modify its optical, electrical, or mechanical properties. These coatings are composed of thin...

Also known as corner-cube reflector or retrodirective reflector. Three reflecting surfaces, perpendicular to each other, that are arranged like the inside corner of a cube. As the triple mirror has a...

A laser that has a surface-emitting semiconductor gain element coupled to an external mirror designed to complete the laser resonator. VECSELs can be electrically or optically pumped. The extended...

A two-sided mirror suspended by a pendulum mechanism. An autocollimator set normal to such a mirror surface will, by definition, have its optical axis set horizontal.

A type of surface-emitting laser diode that uses dielectric mirrors to produce surface emission. The laser cavity is established in a vertical direction with respect to the plane of the active region.

A system used for gratings that consists of a concave mirror, a grating and a plate holder mounted normal to the grating to reduce astigmatism and spherical aberration. The mounting yields a...

A beamsplitting mirror that reflects as a function of wavelength.

After putting a thick photographic emulsion on a front-faced mirror, and exposing the emulsion to monochromatic incident light normal to the face, Wiener discovered, upon developing the emulsion,...

A grazing incidence mirror telescope with concentric conic surfaces having a single common point: a paraboloid-hyperboloid combination with two internal reflections.

A Cassegrain telescope having a parabolic primary mirror, a spherical secondary mirror and a zero-power doublet in the converging bundle for aberration correction.

A mirror that supplies equal reflectance for both the S-polarization and the P-polarization of a laser for a defined angle of incidence, usually 45°.