Photonics Dictionary

A compound prism formed by cementing together two 30° prisms, one of right-handed and one of left-handed quartz. It has good ultraviolet-transmitting qualities and no double refraction.

Law relating the illuminance (or irradiance) of a surface to the cosine of the angle, q, between the normal to the surface and the direction of the incident wave.

The least angle of incidence at which total internal reflection takes place. The angle of incidence in a denser medium, at an interface between the denser and less dense medium, at which the light is...

Illumination in which the light source is imaged at the object.

The axes of symmetry in a crystal structure. See also biaxial crystal; uniaxial crystal.

A lens aberration that causes a flat object surface to be imaged onto a curved surface rather than a plane.

A lens aberration in which the focal length varies radially outward from the center of the field. It has the effect of making a straight tangential line in the object appear curved in the image,...

Custom lapping and polishing services involve specialized processes used to improve the surface finish and dimensional accuracy of components to meet specific requirements or standards. These...

A custom optic refers to an optical component that is designed, manufactured, and tailored to meet specific requirements or applications. These optics can include lenses, mirrors, prisms, filters, or...

A cylindrical lens is an optical component that has different curvatures along its two orthogonal axes, resulting in a shape resembling a cylinder. Unlike spherical lenses, which have the same...

A system incorporated into fiber optic data communications characterized by several spatially distributed terminals that are served with the same multiplexed signal.

A quantitative measurement of the coherence of a light source; equal to the visibility (V) of the fringes of a two-beam interference test: where Imax equals the intensity at a maximum of the...

The number of unique ways in which a part can move in an alignment system. In static alignment, there are six: one in the direction of and one in rotation about each of the X, Y and Z axes. In...

The range of image distances that corresponds to the range of object distances covered by the depth of field.

Design and engineering consulting services refer to professional services provided by specialized firms or individuals to assist clients in various aspects of product development, system design, or...

A detector array refers to a collection of individual detector elements arranged in a two-dimensional grid or matrix format. Each element within the array is capable of detecting electromagnetic...

A detector-Dewar assembly typically refers to a combination of a detector and a Dewar flask used in scientific instruments, particularly in the field of infrared spectroscopy or other applications...

Diamond turning refers to a precision machining process used to produce complex optical components, particularly lenses and mirrors, from materials such as metals, plastics, and crystalline materials...

A dichroic coating, also known as a dichroic filter or dichroic mirror, is an optical coating designed to selectively transmit or reflect certain wavelengths of light while simultaneously absorbing...

Dichroism refers to the property of certain materials to exhibit different colors or absorbance of light depending on the direction of light propagation or polarization. The term is commonly used in...

As a wavefront of light passes by an opaque edge or through an opening, secondary weaker wavefronts are generated, apparently originating at that edge. These secondary wavefronts will interfere with...

A diffraction grating is an optical component consisting of a surface with a periodic structure of equally spaced, parallel grooves or rulings. These rulings act as an array of closely spaced slits...

Optical elements that use diffraction to control wavefronts. Diffractive optical elements include diffraction gratings, surface-relief diffractive lenses, holographic optical elements and...

A digital camera is a device that captures and records still images or video in digital format. Unlike traditional film cameras, which use photographic film to capture and store images, digital...

A diode laser is a type of laser that uses a semiconductor diode as the active medium to generate coherent light. Semiconductor diodes are electronic devices that conduct electricity primarily in one...

A diode-pumped solid-state laser (DPSSL) is a type of laser system that uses semiconductor diode lasers to pump energy into a solid gain medium, resulting in the generation of coherent light. This...

An assembly of multiple prisms that disperses incident light into its spectral components without deviating light at the central wavelength.

A colorimeter using a spinning disc made of different colored sections for colorimetric analysis.

A measure of the dispersive properties of a glass. The relative dispersion is defined as: where C, D, and F refer to the material's index of refraction at the three chief Fraunhofer lines in the...

A general term referring to the situation in which an image is not a true-to-scale reproduction of an object. The term also is used to connote the temporal alteration of the signal's waveform shape....

A distributed feedback laser (DFB laser) is a type of semiconductor laser diode designed to emit coherent, narrow-bandwidth light with precise control over the wavelength. It achieves this through a...

A diverging lens is a type of lens that causes parallel rays of light to spread out or diverge. It is thinner in the center than at the edges and is commonly referred to as a concave lens. The most...

A general-purpose lens, also known as the Celor lens, used widely in photography and commercial processing; it has the form of a triplet with a split flint element.

The separation of unpolarized light into two plane-polarized elements by a doubly refracting crystal. When a crystal, such as calcite, is placed between the eye and a pinhole in a card, two bright...

A method of fabricating an optical waveguide by melting the core and clad glasses in two suitably joined concentric crucibles and then drawing a fiber from the combined melted glass.

A fast, wide-angle lens used in television and photographic cameras, with excellent overall correction, but subject to residual oblique spherical aberration.

A form of prism invented by H.W. Dove. It resembles half of a common right-angle prism in which a ray entering parallel to the hypotenuse face is reflected internally at that face and emerges...

An optical system having two sets of components separated by an air space, while successive lenses in each set are cemented together.

A refracting telescope that uses a prism to bend the line of sight 90°.

A lamp that uses the transmission of an electric current through a gas or vapor to produce illumination. Neon, mercury and argon lamps are examples of electric-discharge lamps.