Photonics Dictionary

Optical manufacturing tools and machinery encompass a wide range of equipment, instruments, and systems used in the fabrication, shaping, finishing, and testing of optical components and systems....

A surface that has no curvature; a surface that is perfectly flat.

A straight line connecting the curvature centers of the refracting lens surfaces. In a mechanical sense, a line joining the centers of a lens as it is placed in a mount. The principal axis is the...

A metal device of convex or concave curvature to which lens castings or semifinished lenses are cemented with only their edges in contact with the device.

Also known as a turned-down edge. A rapid change of curvature near the edge in a lens or prism surface.

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.

In multifocal spectacles, a term used to denote glass with a high refractive index that has been fused to the blank and ground to a curvature, resulting in added power.

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...

A formed piece of glass, one surface of which has been ground and polished to the required curvatures.

A term used to denote a concave surface having too long a radius of curvature. That is, its negative power is too small or low.

A term used to describe a convex surface having too short a radius of curvature. To correct this condition, material is cut from the outer portion of the polishing tool.

A function of the intensity distribution in an image aberrated by a quadratic curvature wavefront distortion.

A convention that defines specific dimensions of an optical system, such as the image distance or radius of curvature of a lens or mirror, as negative or positive to facilitate calculations based on...

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 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,...

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 transparent block shaped accurately to reverse curvatures of the components it is used to test. By contacting an accurately finished negative lens shape with a newly made positive, the conformity...

A surface that is swept out by revolving a circle about an axis that lies in the plane of the circle but that does not intersect its center. The result is a surface having different curvatures in...

The process by which a surface is made to conform accurately to a given curvature.