Photonics Dictionary

The average intensity of a light source measured over all directions.

The average luminous intensity of a point light source measured over all directions.

An anastigmatic lens with a thick meniscus construction that flattens the field and corrects chromatic and spherical aberration.

A metalens, short for "metasurface lens," is a type of optical lens that uses nanostructured materials to manipulate light at a subwavelength scale. Unlike traditional lenses made of glass or other...

A microbubble resonator is a device used in photonics and optical physics for the precise manipulation of light waves. It consists of a micro-sized, gas-filled spherical cavity (the "microbubble")...

Mie scattering, named after the German physicist Gustav Mie, refers to the scattering of electromagnetic radiation (such as light) by spherical particles. Unlike Rayleigh scattering, which is...

A form of shearing interferometer that contains a simple wedged (plane-parallel) glass plate with a nonzero optical path difference to create interference between split optical wavefronts. The...

Condition in which a perpendicular surface can be discovered for every ray in a group. This condition is commonly observed when rays emerge from a point source or object that is placed at the center...

A lens used in the optical testing of an aspheric surface. It converts a spherical wavefront into one that precisely matches the surface under test. When the wavefront is reflected from that surface,...

The image error that results from astigmatism, coma, oblique spherical aberration, lateral color and distortion.

coma, fifth order aberration with on-axis focal point variation with incident off axis ray height position

A hemispherical covering that is rotatable about a central axis. There is a slit opening along one side wide enough to allow a telescope to be directed at any vertical angle up to 90°.

Off-axis paraboloid and ellipsoid mirrors are specialized optical components used in various optical systems, particularly in applications requiring precise focusing, collimation, or imaging of...

Optical artifacts refer to undesired or unintended effects that can occur in optical systems, such as microscopes, cameras, telescopes, and other optical instruments. These artifacts can distort or...

A dome-shaped structure used for some optical instruments in place of a flat window. The transparent material should be of good quality and the hemispherical surfaces should be concentric.

The direct computation of the Fourier transform of the space variant system output of an optical processor with a single spherical lens. The one-dimensional output spectrum appears along a 45°...

A concave mirror that has the form of a paraboloid of revolution. The paraboloidal mirror may have only a portion of a paraboloidal surface through which the axis does not pass, and is known as an...

A mold for glass or plastics often made of stainless steel to prevent pitting or oxidation in service. It is polished to the opposite curve of the surface that will be molded, and may be spherical or...

The compression and intensification of a laser pulse of a specific width into a smaller pulse width. A spherical cavity, in conjunction with a beam compressor, is efficient for pulse amplification....

The transform defining that, if a reference beam is a divergent spherical wavefront, then the reconstructed image will be the equivalent of the near-field diffraction pattern of the object. Also...

The restriction of wavefront error to within a quarter of a wavelength of a true spherical surface to assure essentially perfect image quality.

An optical system that is corrected for distortion and spherical aberration and therefore forms the image of a straight line as a straight line.

A form of Cassegrain telescope having a concave hyperbolic primary and a convex hyperbolic secondary. This form permits the simultaneous correction of spherical aberration and coma.

Robotic arms, also known as robot arms or manipulator arms, are mechanical devices designed to mimic and perform the functions of human arms. They consist of multiple articulated segments, joints,...

Scalar diffraction theory is a simplified approach used to describe the propagation of electromagnetic waves, particularly light, as they encounter obstacles or apertures. It is termed "scalar"...

A camera that consists of a concave spherical mirror with an aspheric plate situated at the center of curvature of the mirror. The purpose of the plate is to correct the spherical aberration of the...

An aspheric plate placed at, or near, the center of curvature of a spherical reflector and used to correct for spherical aberration.

Seidel aberrations refer to a set of monochromatic aberrations in optical systems, named after the German mathematician and physicist Ludwig von Seidel. These aberrations describe deviations from...

The process of making an abrupt break in a spherical surface on a spectacle lens so that a new center of curvature is set for a portion of the lens. This has the effect of adding a prism to that...

A filter that creates spherical aberration resulting in an image with a soft outline.

A lens that exhibits spherical aberration when used at large aperture settings, and that forms an image with a slightly blurred outline.

A spheric lens, also known as a spherical lens, is a type of optical lens with at least one surface that is part of a sphere. This means that the lens surface is curved in a symmetrical manner,...

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...

In gradient index optics, a gradient profile in which the refractive index varies symmetrically about a point.

A tiny lens (as small as 100 µm in diameter) used to focus light on charge-coupled devices, formed by heating a photosensitive material exposed through a mask, leaving a pattern of raised...

A lens aberration. The chromatic variation of spherical aberration.

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 polishing machine with a lens mounted on a wooden stick, allowing a very wide sweep. It is used to polish hemispherical or hyper-hemispherical surfaces.

A method used in surface quality testing for accurate positioning and rotation of metal spheres about an axis or fixed point in space that involves a sliding contact between the indicator and tip and...

A symmetrical, very wide-angle lens. Well-corrected for spherical aberration and color, the Topogon can cover fields up to 90° at speeds from f/11 to f/6.3.

A method of measuring total hemispherical emissivity of the plane surface of a solid that consists of thermally isolating a specimen of the material inside a vacuum, preheating it slightly above the...

A precision lens designed to convert the plane wavefront output of an interferometer to a spherical wavefront for the testing of curved (spherical) surfaces.

A compound lens consisting of two negative lenses of flint glass. A double-convex lens of crown glass is cemented between the two negative lenses. With this system, it is possible to decrease...