Photonics Dictionary

An astronomical body that emits radiation concentrated by a strong magnetic field into two beams that rotate, giving a pulsing effect.

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....

System of information coding in which the signal is sampled 8000 times per second and the samples quantized by referring them to a series of preset 8-bit codes. Thus digitized, the signal is sent to...

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.

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...

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...

A pump laser is a type of laser used to provide the necessary energy to the gain medium of another laser or laser system, initiating the process of stimulated emission and producing laser light. The...

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...

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...

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...

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...

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...

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...

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...

A quantum dot is a nanoscale semiconductor structure, typically composed of materials like cadmium selenide or indium arsenide, that exhibits unique quantum mechanical properties. These properties...

Quantum efficiency (QE) is a measure of the effectiveness with which a device or system, typically in the context of photonics or electronics, converts incoming photons (light) into a useful output...

Quantum key distribution (QKD) is a method of secure communication that utilizes principles from quantum mechanics to establish a shared secret key between two parties, typically referred to as Alice...

The area of optics in which quantum theory is used to describe light in discrete units or "quanta" of energy known as photons. First observed by Albert Einstein's photoelectric effect, this particle...

A quantum repeater is a crucial component in quantum communication networks, designed to extend the range over which quantum information can be transmitted. Quantum information, typically carried by...

Quantum sensing refers to a class of sensing technologies that leverage principles from quantum mechanics to enhance the precision and sensitivity of measurements. Traditional sensors operate based...

A quantum well is a structure in quantum mechanics that confines particles, such as electrons or holes, in one spatial dimension. This confinement leads to quantized energy levels, creating a...

Quantum-enhanced metrology refers to the use of quantum mechanics principles and techniques to enhance the precision and sensitivity of measurements in metrology—the science of measurement....

A plate made of a double-refracting crystal having such a density that a phase difference of one-quarter cycle is formed between the ordinary and extraordinary elements of light passing through.

A contraction of quasi stellar. An astronomical object that appears to be a star but has a different, larger redshift.

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...

The transform defining that, if a reference beam is a divergent spherical wavefront, then the reconstructed image will be the equivalent of the near-field diffraction pattern of the object. Also...

A quasiparticle is an emergent phenomenon that occurs in many-body systems, particularly in condensed matter physics, where the collective behavior of a large number of interacting particles can be...

A qubit, short for quantum bit, is the fundamental unit of information in quantum computing and quantum information processing. Unlike classical bits, which can exist in one of two states (0 or 1),...

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...

Rabi oscillations are a fundamental phenomenon in quantum mechanics that describe the periodic and reversible exchange of energy between two quantum states when subjected to an oscillating external...

An acronym for radioactive detection, identification and computation. The term refers to the detection and measurement of the intensity of emitted nuclear radiation.

A statistical analysis of facts obtained when the intensity of x-ray diffraction is calculated at different angles. In this way, the interatomic distances of gases and liquids can be deduced, with...

Ratio of the radiance of the specimen to that of a perfect reflecting or transmitting diffuser identically irradiated.

That process by which radiation spontaneously emitted by a volume of optical materials is resonantly reabsorbed within the same volume before it escapes. This effect is manifested in a reduction in...

An instrument used to detect radioactive materials: alpha particles or helium nuclei; beta particles or free electrons; and gamma rays, which are x-rays of very short wavelength. They may be detected...

A flexible fiber cable with a small diameter that transports light from the excitation laser to the target. Used in Raman spectroscopy, the probe is capable of obtaining high-quality data at high...

A device that changes the frequency of light by inducing the Raman effect on a beam passing through it.

A photographic camera and processing system used to form a usable record of the subject in a short time, usually a few seconds, for immediate analysis.

Rare earth dopants refer to elements from the lanthanide series, also known as rare earth elements, that are intentionally introduced into the crystal lattice of a material to modify its properties....

An electronic device that minimizes short-term drift effects and random measurement error inherent in alternate ellipsometric measurement of two signals.