Photonics Dictionary

A mappable surface feature arranged in straight or curved lines that is distinguished from surrounding surfaces and is formed as a result of the landform's internal characteristics.

A device for which the output electric field is linearly proportional to the input electric field, and no new wavelengths or modulation frequencies are generated.

A linear image sensor is a type of solid-state electronic device used to capture and convert light into electrical signals. Unlike area image sensors (such as CCD or CMOS sensors), which capture an...

Linear motion is the movement of an object or particle along a straight path in a single direction. It is one of the simplest forms of motion, described by parameters such as displacement, velocity,...

Linear optics refers to the study and manipulation of light in a linear and deterministic manner, where the response of optical elements is proportional to the amplitude of the incident light wave....

A term for thermoplastic optical materials; that is, those in which the polymer chains remain linear after heating and molding and which thus can be remolded again and again, unlike thermoset...

A linear positioning stage, also known as a linear stage or translation stage, is a precision mechanical device used to accurately move and position objects along a linear axis. These stages are...

Linear receive optics typically refers to the optical components and systems used in the reception (detection) of linearly polarized light signals in various applications, such as optical...

Linewidth, also known as spectral linewidth or line width, refers to a measure of the width of a frequency spectrum of a signal or a resonance. It indicates the range of frequencies over which the...

A Michelson-type interference microscope used to produce interference patterns of reflective specimens through the interference between light reflected by the specimen and that reflected by a...

A defect in the cleaved end face of an optical fiber, in the form of a sharp protrusion at the edge of the fiber.

A self-healing, index-matching, nonporous coating for optical components that can eliminate production difficulties and deficiencies associated with solid-film contamination and postdeposition...

Multimode straight fiber capable of transporting linearly polarized light with any incident polarization angle, and in which no form of internal stress can develop that could lead to birefringence.

Liquid crystals are a state of matter that exhibits properties intermediate between those of conventional liquids and solid crystals. In a liquid crystal, the molecules are ordered like those in a...

An alphanumeric display formed by a layer of liquid crystal material sandwiched between two sheets of glass; a transparent conductive coating on the glass is etched to form the character segments. An...

A liquid crystal light valve (LCLV), also known as a spatial light modulator (SLM), is an optical device that modulates the intensity, phase, or polarization of light passing through it using liquid...

Liquid crystal on silicon (LCoS) is a display technology that combines liquid crystal materials with silicon-based semiconductor technology to create high-resolution, high-quality images. LCoS...

Liquid marble refers to a unique form of microscale liquid encapsulation, where small droplets of liquid are coated with a fine layer of hydrophobic powder, such as silica nanoparticles or Teflon....

A mirror composed of liquid, taking advantage of the parabolic shape of a spinning liquid and the fact that the mirror's focal length can be adjusted by altering the velocity at which the liquid's...

Liquid or fluid optics refers to the use of liquids to create or enhance optical systems. These systems leverage the unique properties of liquids, such as their ability to change shape, refractive...

The pattern, formed by a character generation cathode-ray tube system, in which the characters are made up of wave shapes synthesized by a series of sine and cosine terms.

A crystal often used for windows and refracting components in the ultraviolet, visible and infrared. Characteristically, this form has excellent transmission from 0.14 to 6.0 µm.

A crystalline ferroelectric material used primarily as a substrate and an active medium for thin-film optical modulators and switches. It possesses very high electro-optic and piezoelectric...

Lithium triborate (LiB3O5), commonly abbreviated as LBO, is a nonlinear optical crystal widely used in various applications involving frequency conversion of laser light. It is valued for its...

Lithography is a key process used in microfabrication and semiconductor manufacturing to create intricate patterns on the surface of substrates, typically silicon wafers. It involves the transfer of...

A mirror employed with a very high incidence angle to form a pair of coherent light sources by reflection, and therefore forming interference bands.

In coherent optical communications systems, a laser used at the receiving end to produce a steady wave that is combined with the incoming laser signal before detection, generating a composite wave...

A lock-in amplifier is a specialized electronic instrument used to extract and measure small signals embedded in noise or interference. It is particularly useful in fields such as spectroscopy,...

The partial differential equations for the spatial and time dependence of electric and magnetic fields inside a semiconductor. They are the analog of Maxwell's equations, which apply to the electric...

A long-pass filter is an optical filter that allows longer wavelengths of light to pass through while blocking or attenuating shorter wavelengths. These filters are designed to transmit light with a...

Long-wave infrared (LWIR) refers to a specific range of the infrared spectrum. Infrared radiation is divided into three main categories based on wavelength: near-infrared (NIR), mid-wave infrared...

A waveform that can oscillate along the length of the laser cavity.

In image processing, the memory that stores the values for the point processes. Input pixel values are those for the original image, while output values are those displayed on the monitor as altered...

A form of mirage where objects near or just below the horizon appear in enlarged or distorted form because of atmospheric refraction. The glow in the sky caused by the presence of light below the...

The Lorentz oscillator model is a theoretical model used in physics to describe the response of a charged particle (such as an electron) to an oscillating electric field. It is particularly employed...

Low Earth orbit (LEO) refers to a region in space that is relatively close to Earth's surface, typically characterized by altitudes ranging from approximately 180 to 2,000 kilometers (112 to 1,242...

A lumen is a unit of measurement used to quantify the amount of luminous flux, which is the perceived power of light. In other words, the lumen measures the total amount of visible light emitted by a...

A laser effect used especially for laser light shows. Lumia are created by placing a distorting medium such as rippled glass in the path of the laser beam.

A complete unit containing a light source, globe, reflector, housing, socket and other necessary components for lighting.

Luminescence is the emission of light that occurs without the involved substance undergoing a significant increase in temperature. In other words, it is the production and emission of light by a...

A collector for photovoltaic power generation that consists of a thin plate that strongly absorbs sunlight striking its faces and luminesces efficiently. A large fraction of the luminescence is...

Luminosity refers to the total amount of energy emitted by an astronomical object, typically measured per unit time. It quantifies the intrinsic brightness of the object and is often expressed in...

Quotient of total luminous flux divided by total radiant flux; lumens per watt. (For a source, quotient of total luminous flux divided by lamp power input.)

A high-resolution spectroscopic device commonly used in the early 20th century as a component of double-beam interferometers. Light introduced at one end of the plane-parallel glass plate will be...

A dielectric sphere with an index of refraction that varies with distance from the sphere center. A parallel beam of rays is focused on the lens surface at a point diametrically opposite the...

A lymphocyte is a type of white blood cell (leukocyte) that plays a central role in the immune system. Lymphocytes are produced in the bone marrow and mature in the lymphoid organs, such as the...