A pair of telescopes with prismatically erected images, mounted side by side with the eyepieces at the interocular distance of the observer. This separation is adjustable with a convenient millimeter scale. The separation of the objective lenses is...

An early graphic scheme of colors in which saturated spectral colors are plotted around the circumference of a circle....

A small television tube originally developed for closed-circuit television. It is about 1 inch in diameter and 5 inches...

The circle of confusion is a defocused or aberrated image of a point. Focus is generally set where the diameter of this...

The image of a point source that appears as a circle of finite diameter because of defocusing or the aberrations inherent in...

A tiny lens (as small as 100 µm in diameter) used to focus light on charge-coupled devices, formed by heating a...

A microchannel plate (MCP) is a specialized electron multiplier device used in various applications such as particle...

Modified chemical vapor deposition (MCVD) is a technique used in the fabrication of optical fibers. It is a specialized form...

A lens blank is a piece of optical material in a raw, unfinished state, typically in the form of a disk or block, from which...

A flexible fiber cable with a small diameter that transports light from the excitation laser to the target. Used in Raman...

1. Calculated distance between two exactly opposed points on a beam at a chosen fraction of peak power (typically 1/e2). 2....

1. In glass, a solid inclusion having a small diameter. 2. A particular, single crystal that, after undergoing the...

Denoting a finished circular edge. A decentered lens is adjusted on a centering chuck so that its image runs true, and the...

A physical constraint, often a lens retainer, that limits the diameter of the axial light bundle allowed to pass through a...

The limited light-gathering area of an optical system. The area is normally restricted to an edge or outer surface of an...

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

Measure of the interference fringe pattern produced by the forward scattering of light by an optical fiber; the fringe...

A single-particle scattering technique in which an incident laser beam is tightly focused by means of lenses to yield a...

A method of producing magnified images by x-rays. The specimen is placed close to a point source of x-rays; the...

In photoelectric sensing, the portion of the transmitted beam that actually functions in the system; the diameter of the...

A system of optical components designed to increase the diameter of a radiation beam. Usually an afocal system.

A broken circle used as the test object in distinguishing visual acuity. The width of the gap in the circle is equal to the...

An astronomical mirror, also known as a telescope mirror or primary mirror, is a key component of a reflecting telescope. It...

A figure of merit corresponding to the amount of light seen by a viewer through binoculars. A higher number indicates a...

An imaging system designed to highlight small deviations in a planar reflective object such as a mirror. The system can be...

High-modulus elastic fibers that exhibit the following differences from conventional elastic fibers: Increasing temperature...

The maintenance of a fixed-phase relationship across the full diameter of a cross section of a laser beam.

Laws that predict the maximum power output as a function of tube diameter for a hydrogen cyanide laser of a given discharge...

In the region of a Gaussian beam focus by a diffraction-limited lens, it is the axial distance from the point of minimum...

An accurately produced hole of any size and shape that is used as a masking device in an optical system. Pinhole apertures...

Consists of a pair of radio telescopes concentrated on a single celestial object. This technique creates a single radio...

1. A lens situated at or near the plane of an internal image to project the aperture of a previous objective or erector upon...

A coherent fiber optic bundle made from fibers whose diameter changes gradually along its length. Used to magnify or reduce...

A lens made from transparent plastic material. Lenses over 31/2 in. in diameter are usually machined, ground and polished....

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

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...

Also known as f number, lens speed is commonly represented as the ratio of the focal length to the diameter of the lens....

An optical assembly refers to a collection of optical components that are carefully arranged and aligned to perform a...

Increase in the diameter of an initially collimated beam, as measured in milliradians (mrad) at specified points; i.e.,...

An atomic force microscope (AFM) is a high-resolution imaging and measurement instrument used in nanotechnology, materials...

A technique used to measure the mode-field diameter of an optical fiber by scanning one fiber past another at a distance of...

A small low-power microscope or magnifier with a scale that is used to measure the exit pupil diameter and eye relief on...

The restricting opening at the rear of a lens or prism that is commonly defined as the maximum diameter of the emergent cone...

A standard lens interface initially made for 16mm movie cameras and now used primarily on closed-circuit television cameras....

Optical components exceeding 24 in. in diameter. The components are usually glass, acrylic or polystyrene and are used for...

The smallest linear diameter to which a laser or other beam of radiant energy is capable of being focused, depending on the...

An instrument for measuring the diameter of the human eye pupil.

Beam profiling is a technique used to characterize and analyze the spatial intensity distribution of a laser beam. It...

The ratio of the diameter of the entrance pupil in an optical system to the equivalent focal length of that system. The...

That point in a Gaussian beam where the wavefront has a curvature of zero and the beam diameter is a minimum.

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

A sputtering target is a solid material used in the process of physical vapor deposition (PVD), specifically sputtering....

The description of the refractive index along a fiber diameter.

In microscopy, the measured distance between theoretical parallel lines that are drawn tangent to the particle profile and...

When a lens system with a circular aperture is free of aberrations, the image of a point object will appear as a disc of...

A small object that behaves as a whole unit or entity in terms of it's transport and it's properties, as opposed to an...

The condition of the numerical aperture or beam diameter of the laser, LED, or other optical source being larger than the...

In the context of electronics and semiconductor manufacturing, a wafer refers to a thin, flat disk or substrate made of a...

The angular field of view that is seen by the eyes when fixed on a point straight ahead. The normal binocular visual field...

A mechanical device designed to smoothly vary the effective diameter of a lens, thereby controlling the amount of light...

The expression denoting the ratio of the equivalent focal length of a lens to the diameter of its entrance pupil.

A low-power magnifier that usually has a large diameter.

A cosmetic defect on the surface of an optical element. A dig is nearly equal in terms of its length and width. The size is...

A fiber optic cable assembly refers to a complete unit consisting of optical fibers, connectors, protective jackets, and...

Light diffracted by a solid (usually quartz in crystal or fused form) traversed by acoustic waves. If the ultrasonic...

Any crystalline material whose length is much less than its measured diameter.

A device for measuring linear dimensions. The optical caliper generally consists of two circularly mounted mirrors whose...

The distance between the center of the two concentric circles of an optical fiber that designate the diameter of the...

An Abbe condenser in which the upper lens element is fixed. The lower lens may focus the illumination between the elements...

That object distance at which a camera must be focused so that the far depth of field just extends to infinity. The near...

A specific method for measuring the diameter of irregular shaped particles, Martin's diameter is the measured distance...

Laser optics refers to a broad category of optical components and systems designed for manipulating and controlling laser...

The restricting aperture located at the front of the lens. It is usually defined as the maximum diameter of the entrance...

A rotating disc that holds several lenses of differing focal length about a diameter. Used to switch lenses in a system...

For a single-mode fiber, the measurement of the irradiance distribution at the fiber's end face.