Photonics Dictionary

A computer-generated, phase-and-amplitude, off-axis hologram made by a multi-exposure technique that uses three computer generated transmission masks. Each mask controls one fixed-phase component of...

A method used to detect internal or residual microstresses in a material by using a laser beam to locate changes in polarization caused by the stress.

A zone plate produced by a computer and having a binary structure that can be etched into a chromium or quartz layer. It often is used in laser machining, in which the machining of small holes with...

A type of fiber optic sensor that detects alteration in position, distance, pressure, liquid level or temperature by transmitting light across a gap to a reflector; a change in the light returned to...

A direct method of measuring refractive index that works best with flat-surfaced samples (i.e., those that are not dependent on special prism shapes) and produces data that are uniquely sensitive to...

A type of fiber optic sensor that responds to a change in the intensity of received light caused by the displacement or other phenomena being measured.

A type of fiber optic sensor that detects changes in pressure, vibration, sound level or acceleration by monitoring the ejection of light from the fiber core to the cladding caused by microbending...

A phase-modulated sensor is a type of sensor that uses modulation of the phase of a signal to measure changes in a physical quantity. In such sensors, variations in the phase of the signal are...

A glow discharge lamp consisting of a cold cathode and a mixture of inert gases. The intensity of illumination varies with the applied signal voltage. This lamp was commonly used as a source of...

A receiver for optical communications systems consisting of a symmetric binary, pulse-code-modulated transmitter, a log-normal channel and an array of independent photocounting detectors that yield...

The simplest method of transmission on a local area network. The entire bandwidth of the cable is used to transmit a single unmodulated digital signal. Baseband transmission is capable of...

An analog signal capable of being modulated as to frequency, amplitude or phase to carry information.

A fiber optic communications system that works on the principles of homodyning or heterodyning. The transmitting laser produces an optical wave that is modulated in amplitude, phase or frequency by...

Continuous wave (CW) refers to a type of signal or transmission where the signal is constant and does not vary with time. In various contexts, the term is used to describe continuous, uninterrupted...

A spatial light modulator consisting of a metallized polymer film stretched over an array of metal-oxide semiconductor field-effect transistors (MOSFETs). Each mirror element in the film can be...

An electro-optic modulator (EOM) is a device used to modulate the amplitude, phase, or polarization of light waves using an external electrical signal. Electro-optic modulation is a fundamental...

The recording of the information contained in a modulated electron beam onto photographic or silicon resin-coated materials. A direct recording method involves the passage of the recording medium...

A fiber Bragg grating (FBG) is a type of optical filter that is inscribed or "written" into the core of an optical fiber. It consists of a periodic modulation of the refractive index along the length...

A fiber optic transceiver, often simply referred to as an "optical transceiver," is a device used in fiber optic communications to transmit and receive data over optical fibers. It integrates both a...

A microscope that uses a flying spot scanner, directed through the eyepiece, as a light source to determine the features of a transparent specimen. The flying spot is modulated by the varying density...

FMCW lidar stands for frequency-modulated continuous wave lidar. It is a type of lidar (light detection and ranging) technology used for remote sensing, distance measurement, and 3D mapping. FMCW...

Free-space optics (FSO), also known as optical wireless communication or optical wireless networking, refers to the transmission of data using modulated beams of light through free space (air or a...

Gain-switching is a technique used in lasers to generate short pulses of light by modulating the gain of the laser medium. This method is distinct from Q-switching and mode-locking, two other common...

Trade name referring to an instrument that determines surface distances by measuring the length of time it takes for a modulated lightwave to reach a mirror and be reflected to its point of origin.

A thermionic tube that has a velocity-modulated electron stream and that may be used as a microwave amplifier or oscillator.

LiFi, short for light fidelity, is a wireless communication technology that utilizes visible light or infrared light to transmit data. Developed as an alternative or complementary technology to...

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...

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,...

A device designed to detect microwave modulation and to mix modulated and unmodulated laser beams. It consists of a photosensitive cathode and a microwave-electron-tube structure that amplifies,...

The highest frequency at which a laser diode can be driven and still be modulated acceptably that further results in the maximum rate of change (modulation) in output frequency that can be obtained...

A modulator is a device or component that modifies a carrier signal in order to encode information for transmission over a communication channel. The process of modulating involves varying one or...

Derivative of the half-tone screen process involving the fabrication of a binary pulse-width modulated copy of the continuous-level input using a halftone screen and spatial-filtering single...

Used in halftone screens to change the fundamental sampled spatial frequency of the halftoned picture, as well as varying the width of the pulse-modulated dots or gratings.

Generation of an acoustical signal by a sample exposed to modulated light.

A system in which the electrical signal embedded within an audio input signal is converted to a modulated light pattern and recorded on film.

An instrument in which visible light beyond the critical angle from a metallurgical microscope is focused on a reference surface. A certain fraction of the incident light tunnels through air to the...

Power modulation refers to the intentional variation of power levels in a signal, often in the context of electronic communication systems. This modulation technique is used to encode information...

A device designed to detect frequency-modulated signals by forming a unidirectional pulse from each sine wave. The direct current of the pulse is proportional to the frequency of the...

A ruticon is an opto-electronic device in which light going through it can be modulated by an electric field. The intensity distribution of the resulting image can be precisely controlled....

In fiber optic communications, a light source whose beam can be modulated and sent along an optical fiber, and the electronics that support it.