Photonics Dictionary

An instrument for plotting the rotatory dispersion of a substance at different wavelengths.

A spectroradiometer is a device used to measure the intensity of light at different wavelengths across the electromagnetic spectrum. It provides a detailed spectral distribution of light, breaking...

The light flash, produced in flash photolysis, that is triggered within a second discharge tube by the third electrode. It is to be differentiated from the photolysis flash which is triggered within...

Spectroscopy is a technique used in the study of interactions between matter and electromagnetic radiation. It involves measuring and analyzing how different materials absorb, emit, or scatter light,...

Spherical aberration is an optical aberration that occurs when light rays passing through a lens or curved optical surface do not converge or diverge to a single focal point. Instead of focusing to a...

A feature in the chromosphere of the sun formed by a jet of gas that reaches from the chromosphere into the corona and has the appearance of a brightly luminous spike.

A defect in the cleaved end face of an optical fiber in which the surface changes abruptly.

A ratio expressing the difference in power between the output fibers of a coupler or splitter.

When splitting the output of a single optical fiber into two or more fibers, the difference in the maximum loss between any two channels.

Radiation emitted when a quantum mechanical system drops spontaneously from an excited level to a lower level. This radiation is emitted according to the laws of probability without regard to the...

A telescopic light-sensing meter used to measure illumination levels of small regions at a distance of many feet; it is used in professional motion picture and television production to ensure proper...

Sputtering equipment is machinery used in the process of physical vapor deposition (PVD), specifically sputtering. Sputtering is a method of depositing thin films of material onto a substrate surface...

A sputtering target is a solid material used in the process of physical vapor deposition (PVD), specifically sputtering. Sputtering targets are typically made of metals, metal alloys, or compounds...

The superimposing of holographic pages in a thick, erasable storage material by changing the reference and object beams. This extends the capacity of holographic memories.

A type of laser used when a great amount of power is required. Avoiding the bulk of large numbers of optical lenses, this instrument offers high-output intensity and a small emitting region at...

STED microscopy, or stimulated emission depletion microscopy, is a superresolution imaging technique in fluorescence microscopy that surpasses the diffraction limit, enabling the visualization of...

The formula that indicates the total radiation at all wavelengths from a perfect blackbody. W Total = 5.67 x 10-12 T 4(W/cm2)

A profile of an optical component, usually a fiber, in which the core is of uniform refractive index and the cladding or surrounding optical surface of a different, usually lower, index.

1. A stereoscope that has adjustable scales to allow the determination of distances and dimensions from stereoscopic photographs. 2. A device used to view pictures of the same section of the night...

The use of a specialized optical microscope designed to provide a more three-dimensional view of a sample. Stereomicroscopy usually uses reflected light and provides enhanced depth perception via the...

The maximum distance at which the stereoscopic effect may be observed. With respect to the unaided human eye, it has been estimated at about 1500 ft.

Vision in depth of three dimensions as a result of the spacing of the eyes. This spacing allows the eyes to see objects from slightly different points of view.

In Stimulated Brillouin Scattering (SBS), an incident photon (usually laser light) interacts with acoustic phonons in a medium. The energy and momentum of the incident photon are transferred to the...

Stochastic optical reconstruction microscopy (STORM) is a superresolution microscopy technique that enables imaging of biological specimens at resolutions beyond the diffraction limit of conventional...

A term referring to the pre-exposed hologram of the subject used in holographic interferometry.

The determination of axially symmetric and asymmetric refractive-index distributions by use of interferometry carried out on the basis of the approximation of a straight path of rays passing through...

A streak camera is a specialized instrument used to capture and analyze ultrafast phenomena, such as extremely short pulses of light or rapidly changing events. Unlike traditional cameras that...

In polarization-preserving optical fibers, the element used to induce birefringence. The SAP is highly doped to provide a different coefficient of expansion from the rest of the fiber material; when...

A method of polishing an aspheric surface by mechanically distorting the optic while polishing the surface to a perfect sphere. When the stress is released, the substrate assumes the desired aspheric...

An imperfection in optical glass consisting of a distinct streak of transparent material having a slightly different refractive index from the body of glass. It is caused by improper mixing of...

A device that produces brief flashes of light for observing the behavior of an object during a short interval. One of the most effective means for accomplishing this is a gaseous tube energized by...

The pattern formed by a character generation cathode-ray tube system, in which the characters are composed of a sequence of line segments (strokes) generated by the electron beam motion with time...

Structural color refers to coloration in materials that is not caused by pigments or dyes but is instead a result of the physical structure of the material. In structural color, the interaction of...

The mean square difference in a spatial parameter at points spaced a given distance.

Structured illumination microscopy (SIM) is an advanced optical imaging technique used in microscopy to enhance the resolution of images beyond the diffraction limit imposed by traditional light...

A substrate refers to a material or surface upon which another material or process is applied or deposited. In various fields, such as electronics, biology, chemistry, and manufacturing, the term...

A metal, alloy or compound that loses its electrical resistance at temperatures below a certain transition temperature referred to as Tc. High-temperature superconductors occur near 130 K, while...

Supercontinuum refers to a broad spectrum of light that spans a wide range of wavelengths, typically from the visible to the near-infrared or even mid-infrared regions of the electromagnetic...

Superluminal transmission refers to the hypothetical process of transmitting information faster than the speed of light, which is commonly denoted as superluminal or faster-than-light (FTL)...

An emitter based on stimulated emission with amplification but insufficient feedback for oscillation to build up.

Superresolution refers to the enhancement or improvement of the spatial resolution beyond the conventional limits imposed by the diffraction of light. In the context of imaging, it is a set of...

Waves that propagate along the interface between two different media without radiation with exponentially decaying evanescent fields on both sides.

A representation of the shape of a surface, including any roughness or other irregularities. The profile can be generated by direct measurements, as by a stylus, or by remote measurement, as by an...