Photonics Dictionary

A system that uses the heat from a pulsed laser to weld metals. Because of the rapidity and localization in which the welding takes place, metals of vastly dissimilar melting points can be welded...

In a sequence of laser pulse emissions, the intitial pulse that often helps initiate a reaction at the target surface, whereas the trailing edge maintains the reaction.

Lidar, short for light detection and ranging, is a remote sensing technology that uses laser light to measure distances and generate precise, three-dimensional information about the shape and...

The pulse-to-pulse fluctuations in power distribution among modes of a Fabry-Perot laser, which can result in system-limiting noise.

Mode-locking is a technique used in lasers to produce ultrashort pulses of light with durations on the order of picoseconds, femtoseconds, or even attoseconds. This method synchronizes the phases of...

Nonlinear optical materials are substances that exhibit optical properties that are not linearly proportional to the intensity of incident light. In other words, these materials produce optical...

Optoacoustic, or photoacoustic, refers to a phenomenon and related techniques that involve the generation of acoustic waves in a material induced by the absorption of light. The term "optoacoustic"...

A whole-flow-field technique providing instantaneous velocity vector measurements in a cross-section of a flow that is seeded with micron-sized particles. CCD or CMOS cameras and laser light sheets...

Photoconductive antenna (PCA) is a semiconductor element that generates or detects high-frequency electromagnetic signals. Compact PCAs based on gallium arsenide (GaAs) or indium gallium arsenide...

A pulse having extremely short duration, about 10-13 to 10-10 s, that is produced by mode locking of wide-bandwidth lasers, such as the organic dye and ruby lasers. Picosecond pulses are used in the...

A method of measuring complex sequential photosynthetic reactions by varying the pulse time and wavelength of light generated by a combination of argon-ion and dye lasers.

A plasma accelerator is a type of particle accelerator that uses electric fields and magnetic fields to accelerate charged particles, typically electrons or ions, by exploiting the motion of charged...

For a pulsed laser, the product of the energy per pulse (joule) and the pulse frequency (hertz); expressed in watts.

Acronym for profile resolution obtained by excitation. In its simplest form, probe involves the overlap of two counter-propagating laser pulses of appropriate wavelength, such that one pulse...

The compression and intensification of a laser pulse of a specific width into a smaller pulse width. A spherical cavity, in conjunction with a beam compressor, is efficient for pulse amplification....

A means of achieving higher peak powers and more efficient harmonic generation by narrowing the pulse width and thus increasing the frequency bandwidth of the output of CW mode-locked lasers....

The lifetime of a laser pulse, generally defined as the time interval between the halfpower points on the leading and trailing edges of the pulse.

A series of capacitors and inductors connected to the flashlamp in a pumped Nd:YAG laser system in order to regulate the pulse shape of the current delivered to the lamp at a given operating voltage.

Number of pulses emitted per unit of time by a pulsed laser.

The use of variations in the power supplied to a laser to change the shape of the output pulse. The technique is used in laser welding, for example, to condition a surface by preheating it at a low...

An instrument designed for laser technology that is used to extract single pulses from the laser and transmit a portion of the pulses, thereby reducing the pulse rate to a desirable frequency.

A laser that emits energy in a series of short bursts or pulses and that remains inactive between each burst or pulse. The frequency of the pulses is termed the pulse-repetition frequency.

A technique for depositing a material coating on metal, ceramic, semiconductor or polymer substrates. The interaction of laser energy with the target creates a plume of ablated material that is...

Separation of incident laser pulses by several seconds so holographic plates can be changed and sandwiched between the pulses. This technique combines the short exposure time of pulsed holography...

A type of laser welding that produces short-duration vapor pockets without buildup of heat in the part, useful for parts that are too thick for conduction welding and that move too slowly for keyhole...

A laser with a gain medium consisting of an organic dye, which is carbon-based. The dye is mixed with a solvent, allowing the molecules to diffuse evenly throughout the liquid. The dye medium is...

A current-source thermal detector used to detect and study the pulses obtained from particular lasers.

A device used to rapidly change the Q of an optical resonator. It is used in the optical resonator of a laser to prevent lasing action until a high level of inversion (optical gain and energy...

Q-switched operation, or q-switching, is a technique used in lasers to produce short and intense pulses of light. The term "Q" in q-switching stands for "quality factor," which is a measure of the...

A laser output that occurs when the cavity resonator Q is first kept very low, using rotating mirrors or saturable absorbers, so that the population inversion achieved is greater than usual. A high...

A type of laser diode that operates at long pulsewidths.

A laser that generates a succession of pulses at a high enough repetition rate to appear continuous. The pump source is switched on for short intervals, nominally equal to the lifetime of the...

In the dye laser, the molecule that takes out energy from the triplet state during collisions between the dye and quencher to achieve long-pulse emission.

The inhibition or elimination of one process by another process. The stimulated emission of a laser oscillator can be quenched by a pulse of radiation of the same frequency traversing the oscillator...

A pulsed laser that emits a recurring pulsed output. Frequency of the pulses emitted is known as pulsed recurrence frequency (PRF). When the PRF or duty cycle is very high, repetitively pulsed lasers...

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...

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...

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 single-photon avalanche diode (SPAD) is a specialized type of photodetector designed to detect extremely weak optical signals, down to the level of single photons. SPADs are widely used in...

Any isolated wave that propagates without dispersion of energy. Specifically to photonics, an ultrashort pulse of laser light that propagates through a waveguide without characteristic chromatic...

A color center laser whose output is coupled to an external control laser cavity and then fed back to the main laser cavity to provide enhanced pulse shaping, leading to ultrashort pulse generation.

A semiconductor laser that operates in the infrared and that is pumped with strong pulses of radiation from a second laser. Dependent on quantum-mechanical principles, it can be tuned over a large...

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...

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...