Photonics Dictionary

An array of refractive microlenses that are round, square and hexagonal and as small as 15 µm. They are used for Hartmann testing, laser diode collimation and other applications that require...

A set of algorithms used to study the structural and spatial characteristics of objects in a digitized image for applications including feature extraction and image segmentation in machine vision and...

A photon-counting instrument for use in both space-borne and ground-based photometric and spectroscopic instrumentation. This style of detector is composed of opaque photocathodes for photon to...

An array of optically distinct fibers that are fused into one strand. They are used to keep the resolution efficiency of the smaller, single fibers and eliminate difficulty in handling. Their...

In an optical waveguide,- typically a multimode fiber - the distortion resulting from differential mode delay, i.e. axial rays (modes), with the shortest path length, will have the shortest...

Also known as gatling gun laser. A system that has an array of lasers sharing a common central axis on a rotating Fabry plate to achieve increased laser firing rates by sequential Q-switching.

A uniaxial, birefringent crystal such as calcite or ruby in which the velocity of the extraordinary ray surpasses that of the ordinary ray. This can also be defined as the index of refraction of the...

The nondestructive analysis and recording of industrial components based on the absorption of relatively low-energy neutrons by material having low atomic numbers. The visible image formed by the...

A telescope with a concave paraboloidal objective mirror and a small plane (diagonal) mirror that reflects rays from the primary mirror laterally outside the tube where the image is viewed with an...

A prism invented by William Nicol in 1828 that is made of calcite, the end faces of which are ground to an angle of 68° between one vertical side and the end surface. The prism is cut diagonally...

Of all the rays passing through a lens from an off-axis object point to its corresponding image point, there is always one ray whose direction in the image space is equal to that in the object space....

Any testing method for materials and components that does not damage or destroy the test sample. Some of the methods used are x-ray, ultrasonic, electro-optic and magnetic testing.

A color whose hue is not produced by a single wavelength in the visible spectrum, but is instead produced by mixing the longest (red) and shortest (blue) wavelengths of the spectrum such as any...

The sine of the vertex angle of the largest cone of meridional rays that can enter or leave an optical system or element, multiplied by the refractive index of the medium in which the vertex of the...

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...

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 optical center of a lens, the incident and emergent rays through this point...

Optical design software refers to specialized computer programs used by optical engineers, physicists, and designers to simulate, model, analyze, and optimize the performance of optical systems and...

The fluorographic method whereby the visible image (as opposed to the x-ray image) is photographed by mounting a camera in front of the fluorescent screen.

The relative path difference (or phase shift) traveled between two rays that pass through different mediums from the same object point. For a perfect optical system, the optical path, or distance,...

A transparent crystalline substance that displays the same optical properties (i.e. refractive index) in all directions such that all light rays behave the same in all directions of propagation and...

A transparent crystalline substance in which the refractive index of the optic axis (extraordinary axis) is different from the other two crystal axes. Two polarization directions are allowed for any...

Optics is the branch of physics that studies the behavior and properties of light, including its interactions with matter and its manifestation as both particle and wave phenomena. It encompasses the...

A discipline that combines optics and genetics to enable the use of light to stimulate and control cells in living tissue, typically neurons, which have been genetically modified to respond to light....

A system in which a supplied signal causes the deflection of the electron beam in a cathode-ray tube, thus forming a visible trace on the phosphor screen of the tube and providing for examination of...

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...

Parallel scanning refers to a method of acquiring data or images simultaneously from multiple sources or in parallel, rather than sequentially scanning each source one after another. This approach is...

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

An array of lines in the infrared region of the emission spectrum of atomic hydrogen. Their wave numbers are expressed by the equation: where represents the wave number in the reciprocal centimeters,...

An OLED display formed by creating an array of OLED pixels connected by intersecting anode and cathode conductors arranged in rows and columns. Electrical power is passed through selected pixels by...

A form of dispersing prism, often used in monochromators, that consists of a common right-angle prism with a 30° dispersing prism attached to each of its square faces. The spectrum formed by the...

A Peltier cooler, also known as a thermoelectric cooler (TEC) or thermoelectric module, is a solid-state device that uses the Peltier effect to transfer heat between two electrical junctions. It can...

A chemical substance that exhibits fluorescence when excited by ultraviolet radiation, x-rays or an electron beam. The amount of visible light is proportional to the amount of excitation energy. If...

A technique proposed for studying the atomic structure of crystals by measuring the interference pattern generated when the crystal is illuminated by a burst of finely tuned x-rays. The resulting...

The use of photographic emulsions to detect and determine the amounts of ionizing radiation, such as x-rays and gamma rays, in an area. This is accomplished by exposing the emulsion to the radiation...

A photon sieve is an optical device used in the field of optics and imaging. It's designed to focus and shape light, typically for applications such as imaging or microscopy. The photon sieve...

The photographic recording of data, in binary form, for storage in memory. Exposure is achieved by a cathode-ray tube or by modulating a continuous-wave laser beam with a Kerr cell, both relative to...

Photovoltaic (PV) refers to a technology that converts sunlight directly into electricity using semiconductors. The term "photovoltaic" is derived from the words "photo," meaning light, and...

A pixel, short for "picture element," is the smallest controllable element of a digital image or display. It is a fundamental unit that represents a single point in a raster image, which is a grid of...

The property exhibited by certain birefringent crystals in which the degree with which they transmit polarized light is different, depending on whether the ray is ordinary or extraordinary. An...

A uniaxial, birefringent crystal having an ordinary ray with a higher velocity than the extraordinary ray.

Basically, a hydrogen atom with two alterations, positronium is the lightest atom in the universe and has an extremely light positron in its nucleus that replaces hydrogen's proton so that its atomic...

A camera system that uses a fine powder to diffract x-rays from the specimen. A beam of monochromatic x-rays passes through a collimator onto the specimen. Diffracted x-rays are recorded on the film...

A technique used in radiography to determine a crystal's structure by obtaining radiographs of it in powder form, normally by the use of a powder camera that forms an image of the crystal's x-ray...