Definitions

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.

Factor that relates the pulse spread occurring in a graded-index fiber to that of an equivalent step-index fiber having an identical refractive index difference between core and cladding (that is, an...

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.

Variations in a signal passing through an optical fiber caused by the effect on the pulse of the fiber's material and mode propagation characteristics.

A noncontact, nondestructive method of measuring defects in thin composite materials, using a xenon flashtube to generate heat in a sample. A thermal imaging system detects differences in the rates...

The interval of duration of a pulse.

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...

The integral of the radiance over exposure time.

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 group of energy levels to which ions in the ground state are initially excited when pumping radiation is applied to a laser medium. The pumping band usually lies higher in energy than the levels...

Radiation used to excite an optical or laser material to a higher energy level. See optical pumping.

1. In the eye, the opening in the iris that permits light to pass and be focused on the retina. 2. In a lens, the image of the aperture stop as seen from object and image space.

An instrument for measuring the diameter of the human eye pupil.

Pushbroom scanning is a technique used in remote sensing and imaging systems, particularly in satellite and aerial sensors, to capture images of the Earth's surface or other objects. In pushbroom...

Pyramid error in optics refers to an aberration in the shape of an optical surface, particularly in the context of mirrors. It is a type of distortion that can occur when the surface of a mirror...

Trade name for a type of borosilicate glass manufactured by Corning Glass Works, noted for its low coefficient of thermal expansion. Used most often for mirror blanks; not suitable for light...

An instrument for measuring the intensity of solar radiation.

Unlike the thermocouple or bolometer, the pyroelectric infrared detector is a current source with an output proportional to the rate of change of its temperature. Capable of extremely rapid response...

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

A process that employs heat to remove polyimide plastic coatings from silica optical fibers and capillary tubing.

The figure of merit of a resonator, defined as (2p) x (average energy stored in the resonator)/(energy dissipated per cycle). The higher the reflectivity of the surfaces of an optical resonator, the...

Device in which contact ionization of atomic particles and thermionic electron emission are used to produce magnetically confined plasma that is greatly ionized.

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...

Q-switching, short for "quenching-switching," is a technique used in lasers to generate short, high-energy pulses of light. The term "Q" refers to the quality factor of the laser cavity, which...

Conceptual formulas that characterize both the transmittance functions of lenses and propagation in the Fresnel zone.

Denoting a phase shift of 90°.

A device used in electron microscopes and particle accelerators to focus electron beams by the arrangement of four electrodes of alternating signs around the electron beam.

The region of the cathode-ray tube phosphor screen restricted by the tube and instrument specification.

Quantitative phase imaging (QPI) is an advanced imaging technique used in microscopy to measure and analyze the optical phase information of transparent specimens. Unlike traditional brightfield...

A device with a limited number of possible output values (sometimes able to be selected) that can translate an incoming signal into these values or codes for outputting. See pulse code modulation. In...

The term quantum refers to the fundamental unit or discrete amount of a physical quantity involved in interactions at the atomic and subatomic scales. It originates from quantum theory, a branch of...

A quantum cascade laser (QCL) is a type of semiconductor laser that operates based on the principles of quantum mechanics. It is a versatile and powerful device used for emitting coherent light in...

Quantum confinement refers to the phenomenon in quantum mechanics where the motion of charge carriers, such as electrons or holes, is restricted to a region of space that is smaller than their...

A photodetector in which an electrical charge is produced when incident photons change electrons within the detecting material from nonconducting to conducting states. See photoconductive detector;...

Quantum dot light-emitting diode (QLED) is a display technology that utilizes quantum dots, which are semiconductor nanocrystals, to produce vibrant and high-quality images. QLED displays are...