Photonics Dictionary

1. A polariscope consisting of a Savart plate and a tourmaline plate analyzer, and used to produce parallel color fringes by transmitting polarized light. 2. A polariscope composed of an analyzing...

Scalar diffraction theory is a simplified approach used to describe the propagation of electromagnetic waves, particularly light, as they encounter obstacles or apertures. It is termed "scalar"...

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.

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...

Seidel aberrations refer to a set of monochromatic aberrations in optical systems, named after the German mathematician and physicist Ludwig von Seidel. These aberrations describe deviations from...

Self-phase modulation (SPM) is a nonlinear optical phenomenon that occurs when an intense laser beam passes through a medium, causing a change in the phase of the light due to its interaction with...

A method of demonstration or examination using a point source illumination without the use of any projection lens between the object and its shadow, the shadow being cast on a distant screen.

Short wavelength infrared (SWIR) refers to the portion of the infrared spectrum that encompasses wavelengths roughly between 1,000 and 3,000 nanometers (nm). In the electromagnetic spectrum, infrared...

Calculation of peak and average transmission power at a given point along an optical fiber or cable.

Silicon carbide (SiC) light-emitting diodes (LEDs) are semiconductor devices that emit light when an electric current is applied to them. These LEDs are made using silicon carbide as the...

First stated by Abbe, condition states that the ratio of input and output angles, from object point to image point, for two arbitrary rays must be equal.

Single molecule localization microscopy (SMLM) is a group of super-resolution microscopy techniques that surpass the diffraction limit of traditional optical microscopes, allowing for the...

The incident ray, the normal to the refracting surface at the point of incidence of the ray at the surface, and the refracted ray all lie in a single plane. The ratio of the sine of the angle between...

Calculated at a given point in a medium as the instantaneous pressure at that point in the presence of a sound wave, minus static pressure at that point.

Spatial resolution refers to the level of detail or granularity in an image or a spatial dataset. It is a measure of the smallest discernible or resolvable features in the spatial domain, typically...

The correlation of radiation between the phases of monochromatic radiation emanating from two separate points.

Spatially offset Raman spectroscopy (SORS) is a technique that extends traditional Raman spectroscopy by incorporating measurements at different spatial offsets. This method allows for the selective...

Spectral repeatability refers to the consistency and reproducibility of spectral measurements across multiple trials or instances. It is a measure of how well a measurement instrument or system can...

A spectral signature, in the context of remote sensing and spectroscopy, refers to the unique pattern or characteristic spectral response of a material or object across different wavelengths of the...

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 sphere. This means that the lens surface is curved in a symmetrical manner,...

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...

In gradient index optics, a gradient profile in which the refractive index varies symmetrically about a point.

A method of evaluating image quality whereby a large number of rays are traced through a lens from a single object point, and their intersections with the focal plane are plotted and analyzed.

The distribution of energy about the image of a point source in the focal plane of an optical system.

The visual examination by a trained observer of the image of a point source. Any coloring or departure from the Airy disc rings indicates the presence of aberrations in the lens forming that image.

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

A rangefinder similar to a pair of binoculars with a long base, a dot or other wander mark provided in each eyepiece field, together forming an apparent point in space. When one dot is moved...

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.

The ratio of the illuminance at the peak of the diffraction pattern of an aberrated point image to that at the peak of an aberration-free image as formed by the same optical system.

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

A method used in surface quality testing for accurate positioning and rotation of metal spheres about an axis or fixed point in space that involves a sliding contact between the indicator and tip and...

An instrument consisting essentially of a photoelectric cell filtered to respond to a specified wavelength region, an amplifier of sufficient gain to provide power enough to control movement of a...

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...

An imaging technique in which an object moving through an interference field formed in space scatters light and is spatially recorded on a photographic film as a hologram. If the interference field...

In optics, a shape often given to the leading edge of a projectile. In any side view it appears as a pointed arc, while any cross section perpendicular to its long axis appears as a circle.

A telescope lens is a primary optical component of a telescope system that gathers and focuses light to form an image. It is typically a curved, transparent piece of glass or other optical material...

Terahertz (THz) refers to a unit of frequency in the electromagnetic spectrum, denoting waves with frequencies between 0.1 and 10 terahertz. One terahertz is equivalent to one trillion hertz, or...

An optical matrix that does not require perfection in both states of the crosspoint, so that all the optical switches can be tap-off devices in which a fraction of the optical energy is transferred...

The production of an image on a magnetic film that is exposed to infrared radiation and heated to a point above Curie temperature in regions of the image. The image is contacted with paramagnetic...

In laser damage testing, the exposure of many sites of a sample to different intensities of laser irradiation to discover the point at which the laser induces failure of the material.

The time domain is a concept used in signal processing and analysis to describe signals in terms of their behavior over time. In the time domain, signals are represented as functions of time, showing...

Technique that defocuses activity from surrounding planes by means of the relative motions at the point of interest.

Topology is a branch of mathematics that focuses on the properties of space that are preserved under continuous deformations, such as stretching, crumpling, and bending, but not tearing or gluing....

Image displacement by a decentered lens, rotated on a chuck whose axis of rotation passes through the geometrical center of the rim of the lens, when the light source is at an infinite distance. It...

Total internal reflection fluorescence (TIRF) microscopy is an advanced fluorescence microscopy technique that leverages the principle of total internal reflection to selectively illuminate and image...

A transducer is a device or component that converts one form of energy into another. It is commonly used in various fields, including electronics, acoustics, and instrumentation, to facilitate the...