Photonics Dictionary

1. Generally, an emulsion mask having a clean annular region in an otherwise opaque region. It is designed to eliminate undesired information. 2. A pinhole in a metal plate, placed at a focal plane...

A spatial light modulator (SLM) is an optical device that modulates or manipulates the amplitude, phase, or polarization of light in two dimensions, typically in the form of an array. SLMs are...

Also known as transverse mode. The configurations of energy storage, relative to the structure of a laser resonator, that define the relative intensity distribution of the laser beam.

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...

In laser systems, the granular effect that is noted when observing the expanded cross section of a laser beam.

Refers to the variety of techniques that use the interference pattern produced by laser light diffusely reflected by an object. There are two basic techniques: direct laser photography, used when...

Spectral flow cytometry is an advanced flow cytometry technique that expands the capabilities of traditional flow cytometry by utilizing spectral information from fluorochromes to enhance...

Gas detection measurement technique that uses a built-in capacitative microphone to calculate the amount of absorbed laser power in a gas cell according to variations of gas pressure.

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,...

A laser resonator in which a mode oscillating between the mirrors will converge upon the laser's longitudinal axis.

A memory system composed of a stack of holographic plates, a mode-locked laser and a rapid detector array. Ultrashort laser pulses are used to extract information from the stack. In this way, storage...

In a laser, the voltage necessary to initiate electrical discharge, somewhat higher than that needed to sustain it.

The degree to which a laser beam is aligned parallel to the housing axis.

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 method of creating real three-dimensional models by using lasers driven by CAD software. In contrast to the normal practice of removing material, this process polymerizes a liquid to quickly...

The purest gas source of antimony, which is used in the manufacture of compound semiconductors for IR sensors and solid-state lasers.

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...

Light from a pulsed laser focused into nonsaturable absorbing fluid that generates a strongly backscattered light beam with a frequency higher than that of the incident light.

A pulsed interferometer that permits the continuous quantitative mapping of the surface deformation of an adaptive optical element (e.g., a deformable mirror) and provides the capability for...

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...

Observed phenomenon in laser pulses in which a large number of excited electrons are created and in which multiphoton processes have produced seed electrons, and excited neutral atoms are...

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...

Surface-enhanced Raman spectroscopy (SERS) is an analytical technique that combines the principles of Raman spectroscopy with the enhancement provided by nanostructured metallic surfaces. Raman...

Instruments used for measuring angles and occasionally lengths on the ground. The principal surveying instruments are the level, the stadia telescope, the transit and the theodolite. Laser...

In a laser, the voltage necessary to sustain a constant operating current, somewhat less than that needed for start-up.

Swept-source optical coherence tomography is an imaging technique used in medical diagnostics, particularly in ophthalmology, to visualize and analyze the internal structures of biological tissues,...

The technique of generating ultrashort -- down to subpicosecond -- pulses by pumping a dye laser with mode-locked laser pumps with cavity lengths the same as, or a submultiple of, that of the dye...

A characteristic of laser output, calculated by dividing the speed of light by the linewidth of the laser beam. The temporal coherence length of different lasers thus varies from a few centimeters to...

A terahertz spectrometer is a scientific instrument used to measure and analyze the properties of materials in the terahertz frequency range, typically spanning from about 0.1 to 10 terahertz (THz),...

The effect that characterizes an intense laser beam that is passed through an absorbing medium, causing the absorbed energy to produce density changes that can alter the intensity distribution of the...

In a laser, a measure of the device's ability to dissipate internally generated heat.

Thin-film coatings are layers of material applied to the surface of an object or substrate, typically to modify its optical, electrical, or mechanical properties. These coatings are composed of thin...

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.

Although low in sensitivity (approximately 10-7 m for helium-neon lasers), this holographic technique permits quantitative assessment of entire vibratory patterns of given structures in a single...

Time-correlated single photon counting (TCSPC) is a technique used in photon counting applications, particularly in the field of experimental physics, biophysics, and fluorescence lifetime imaging...

A time-to-amplitude converter (TAC) is an electronic circuit that converts a time interval between two events into an amplitude or voltage signal. TACs are commonly used in various scientific and...

Tip-enhanced Raman scattering (TERS) is a powerful technique that combines Raman spectroscopy with the enhanced spatial resolution provided by a sharp metallic or dielectric tip. TERS allows...

The study of the optical properties of living tissue. Increased understanding of the behavior of light in this varied, turbid medium, especially its scattering and absorption characteristics, is...

The use of a surgical laser instead of sutures or staples to close a wound or rejoin severed blood vessels.