In gradient index optics, a gradient profile in which the refractive index varies along the direction of light propagation, or optical axis. Axial gradient lenses can be used to correct spherical aberration, spherochromatism and other aberrations.

The physical distance, measured along the optical axis, from the object to the image. Also called overall length.

A reflecting prism that inverts the image. The image is reflected four times internally and emitted laterally. The prism is...

A system of elements which rotates the optical image with respect to the optical axis by a factor of pi radians.

Any ray through an optical system that is not a meridional ray. The plane created by a refracted skew ray does not contain...

The line of vision; the optical axis of a telescope or other observation system. The straight line connecting the object and...

1. The grinding or edging of a lens so that the geometrical center and optical center do not coincide. 2. The shifting of an...

The measured planar or solid angle of related aspects of an optical system with respect to an optical axis.

A variable focal length lens system that retains the object in focus as one or more lenses move as a unit along its optical...

In a microscope, the diaphragm located between the Bertrand lens and the eyepiece, which is closed during conoscopic viewing...

A wedge in a rangefinder or heightfinder used to displace the image produced by one telescope so that it coincides with that...

Seidel aberrations refer to a set of monochromatic aberrations in optical systems, named after the German mathematician and...

Abbreviated TEA CO2 laser. A gas laser that provides shorter pulses and higher peak powers than conventional CO2 lasers. The...

Calculates the exponential growth of the least stable spatial frequency in a laser beam, and is the numerical equivalent of...

Chromatic aberration is an optical phenomenon that occurs when different wavelengths (colors) of light are refracted by a...

A common technique in microscopy, oblique illumination is one in which the object is illuminated by a light source that is...

A straight line connecting the curvature centers of the refracting lens surfaces. In a mechanical sense, a line joining the...

A two-sided mirror suspended by a pendulum mechanism. An autocollimator set normal to such a mirror surface will, by...

In the tolerancing of optical elements, the displacement of the optical axis from the mechanical axis.

There are three types of telecentric lenses: -Image-space telecentric lenses are those in which the aperture stop is...

An erecting prism that inverts and reverses the image. It displaces the optical axis but does not deviate it.

Lens testing equipment refers to a range of specialized tools and instruments used to evaluate the optical performance,...

An equation that uses the wavelength of light passing through a medium, along with a set of coefficients, to calculate the...

In gradient index optics, a gradient profile in which the index varies in a direction perpendicular to the optical axis....

An expression of the tolerance of decentration of a laser diode from the optical axis: the region around the axis in the...

Optical aberration such that image magnification varies with ray distance from the optical axis in a radial distortion.

An optical system with different focal lengths or magnification levels in perpendicular planes to the optical axis.

That plane in an optical system containing its optical axis and the chief ray. Also called the tangential plane.

A paraxial light ray that extends from an object point on the optical axis.

Ray oriented and assumed to propagate orthogonal to the optical axis

An autocollimator is an optical instrument used for measuring small angular deviations with high precision. It operates on...

Also known as TEA laser. A coherent optical source with a wide wavelength range in the infrared, visible and ultraviolet...

An image that is formed when rays emerging from an optical system all converge to a point on the optical axis. A real image...

The point of intersection of the optical axis with any centered optical surface.

1. Mounting a lens or mirror so that its optical axis is coincident with the optical or mechanical axes of other portions of...

The lens thickness measured at the optical axis.

A form of roof prism used to invert an image. The prism has faces cut normal to the optical axis; therefore, the prism may...

Off-axis paraboloid and ellipsoid mirrors are specialized optical components used in various optical systems, particularly...

The alignment process that makes the optical axes of two related systems parallel to each other. Also, making the optical...

The angle between the light input propagation vector and the optical axis of an optical fiber or fiber bundle.

An aerial photograph produced when the optical axis of the camera is perpendicular to the surface below.

A polarizing beamsplitting prism similar in design to the Rochon prism. However, the Senarmont transmits the extraordinary...

A ray that behaves according to paraxial equations; one that lies close to and almost parallel to the optical axis.

That point on the optical axis of a lens, to which an incident bundle of parallel light rays will converge.

An optical instrument, generally a polarizing microscope, that is used to determine the interference figures and optical...

The intersection of the principal plane and the optical axis of a lens.

1. A flaw in a blank caused by folding the blank's surface during its formation. 2. The change in the direction of a...

A continuous-wave dye laser that uses a circulation pump and nozzle to provide an optically flat stream of dye across the...

An angle formed by the lines of sight of both eyes when focusing on an object. Also, the rate at which a ray approaches the...

A straight line, real or imaginary, passing through a body and indicating its center; a line so positioned that various...

The angle between a light ray emerging from an optical system and the optical axis of that system.

A prism or prism assembly that serves to displace the instrument's optical axis.

The maximum variation in thickness of a lens as measured around a diameter centered on the optical axis. The ETD divided by...

In a perfectly centered lens, the mechanical axis (defined by the ground outside the diameter of the lens) is made to be...

The angle measured between the focal surface containing the image and a plane normal to the optical axis.

A reflecting prism that is rhomboidal in shape. It has two parallel transmitting faces, and two parallel reflecting faces;...

A ray that lies in the meridional plane; a ray that lies in the plane that contains the optical axis. A tangential ray.

An image that is formed when rays emerging from an optical system are diverging from the optical axis. The virtual image is...

A mirror mount is a mechanical device used to secure and precisely position mirrors in optical systems. Mirrors are...

A bundle of rays that originates from an object point on the optical axis of a lens system.

The imaginary line passing through both the centers of curvatures of the optical surfaces of a lens or mirror; the optical...

A center-opening shutter made up of several identical leaves that are mounted symmetrically around the optical axis of the...

A form of liquid crystal with an appearance of moving, threadlike structures, particularly visible when observed in thick...

Conventional coordinates for optical system analysis, the X-axis being the horizontal, the Y-axis the vertical and the...

The point on the optical axis of a lens that is the image of the nodal points. For any bundle of rays passing through the...