Photonics Dictionary: P

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.