Photonics Dictionary: S

1. The variation in intensity of a light beam as it travels through the atmosphere. 2. In radiation physics, a light flash formed by an ionizing event in a phosphor; a flash formed when rapidly...

A pinhole camera used to record a radioactive tracer's distribution in a subject by means of a scintillation counter or a fluorescent screen; used when a recording emulsion is not practical.

An instrument designed to measure radiation indirectly through the use of several phosphors and a photomultiplier tube. The absorption of radiation by any phosphors results in light flashes that may...

A scintillation crystal, also known simply as a scintillator, is a material that emits light when it interacts with ionizing radiation such as gamma rays, x-rays, or charged particles. The emitted...

A scintillation detector is a radiation detection device that utilizes scintillation crystals to detect and measure ionizing radiation, such as gamma rays, x-rays, or charged particles. It consists...

A phosphor that has the ability to convert into light emission a portion of energy lost by ionization when a charged particle passes through the material.

The method of determining the energy distribution of high-speed charged particles by the luminous effect formed when the particles strike a material.

An instrument used to test the hardness of various materials. It measures the pressure on a standard point that is necessary to scratch the material.

A device used to take turbidimetric or nephelometric measurements by considering the contrast between a constant brightness field and an illuminated line positioned behind the solution being tested.

The cutting of pitch tooling surfaces by an optical technician to permit polishing compounds to flow across the surface of the tool.

Vision by means of retinal rods; vision of the dark-adapted eye. In scotopic vision, the level of luminance is so low that the retinal cones are not stimulated, and there is no color vision.

An instrument that uses an image intensifier to aid in the viewing of subjects in low-light-level environments.

A defect on a polished optical surface whose length is many times its width. Block reek is a chainlike scratch formed in polishing. A runner cut is a curved scratch caused by grinding. A sleek is a...

Thin layers intended to prevent damage to plastic optics.

The large, usually flat surface onto which an image is projected for viewing. May be reflecting or transmitting (rear projection).

The process of perforating a silicon or ceramic substrate with a series of tiny holes along which it will break. Nd:YAG or CO2 lasers are now routinely used.

Describing a laser in which the gas is permanently sealed within the tube.

The principal point of a lens relative to image space.

A nonlinear label-free imaging technique commonly used during surgical procedures for the visualization of collagen fibers and muscle tissue (myosin) with submillimeter resolution. During the...

Second-harmonic generation (SHG) is a nonlinear optical process that occurs when two photons with the same frequency combine within a nonlinear material, resulting in the generation of a new photon...

Second-order nonlinear optical properties refer to a class of phenomena exhibited by certain materials in response to intense light, typically in the realm of optics and photonics. Nonlinear optical...

The process of grinding the convex surface of a convexo-concave meniscus.

The process of grinding the concave surface of a sphero-cylindrical lens.

Fiber optic cable that operates at the 1300-nm wavelength.

A line formed by the principal (center) ray of an oblique bundle of rays.

The indistinct rainbow that may sometimes be observed outside the distinct primary bow and that has its colors in opposite order. The red colors of both bows are toward each other.

An aberration that remains after primary color is corrected. Primary color causes the back focus of a lens to vary with wavelength; for example, blue light comes to focus closer to the lens than...

Fluorescence produced by a material that has been treated with a dilute solution of fluorescing material.

A self-interference effect that generates random patterns; secondary speckle pattern (SSP) typically occurs in diffuse reflections of a laser on paper, white paint or rough surfaces. By tracking both...

X-rays emitted by a substance that formerly has been exposed to x-rays. The properties of the substance determine the frequency of the rays.