Photonics Dictionary: P

A camera designed to form a continuous record of an expansive section of the horizon. The typical panoramic camera is mounted to rotate about a vertical axis. A slit opening in the film plane and the...

In imaging, the processing of pixel data in such a way that a group of pixels is analyzed at one time rather than one pixel at a time.

Parallel scanning refers to a method of acquiring data or images simultaneously from multiple sources or in parallel, rather than sequentially scanning each source one after another. This approach is...

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...

An array of lines in the infrared region of the emission spectrum of atomic hydrogen. Their wave numbers are expressed by the equation: where represents the wave number in the reciprocal centimeters,...

A Peltier cooler, also known as a thermoelectric cooler (TEC) or thermoelectric module, is a solid-state device that uses the Peltier effect to transfer heat between two electrical junctions. It can...

A wave of radiant energy in which each point of the wave is repeatedly displaced at equal time intervals.

A phage, short for bacteriophage, is a type of virus that infects and replicates within bacteria. Phages are composed of genetic material (either DNA or RNA) surrounded by a protein coat. They are...

In optics and photonics, "phase" refers to a property of electromagnetic waves, such as light, that describes the position of a wave at a given point in time within its oscillation cycle. More...

The use of a reflective device, which can be fashioned from a variety of materials including gases, solids, dyes, aerosols, semiconductor crystals and plasmas, to replicate a laser beam by reversing...

Phase distortion refers to a change in the phase relationships between different frequency components of a signal. In the context of signal processing, it occurs when the phase response of a system...

Phase matching is a crucial concept in the field of optics, particularly in nonlinear optics and the generation of coherent light. It refers to the condition where the phases of two or more waves,...

A phase screen, in the context of optics and wave optics, refers to a surface or medium that introduces a phase delay to an incident wavefront passing through it. This concept is often used in the...

The property of a phosphor that determines its ability to emit light for a time after the stimulus has been extinguished. Persistence may extend to over a minute.

A method for remote measurement of the temperature of moving surfaces in harsh environments by using a laser to stimulate fluorescence of thermographic phosphors and then measuring the decay times by...

The spectroscopic study of the radiation emitted by the lifetime of phosphorescence.

Photobleaching is a phenomenon in which the fluorescence of a fluorophore (a fluorescent molecule or dye) is permanently reduced or eliminated upon prolonged exposure to light. This process occurs...

The study of chemical reactions stimulated by the properties of light.

Photochromic refers to a property exhibited by certain materials, typically organic compounds or dyes, which undergo reversible changes in color when exposed to light. Specifically, photochromic...

The conductivity increase exhibited by some nonmetallic materials, resulting from the free carriers generated when photon energy is absorbed in electronic transitions. The rate at which free carriers...

A photodiode detector is a semiconductor device that converts light into an electrical current. It operates based on the principle of the photoelectric effect, where photons of light incident on the...

Photodynamic inactivation (PDI) is a therapeutic approach that utilizes the combination of light, a photosensitizer, and molecular oxygen to induce cell death or inactivate microorganisms. This...

A system having a photoelectric detector for the measurement of three quantities related by linear combination to tristimulus values of a sample.

A phototube in which the primary photoemission current, before being extracted at the anode, is multiplied many times.

The force that stimulates the emission of an electrical current when photovoltaic action creates a potential difference between two points.

The product of exposure time and irradiance or illuminance.

A measure of the total light passed by a shutter during an exposure, compared with the light that could be passed by an idealized, infinitely fast shutter fully open for the same extreme time.

Photoimmunotherapy (PIT) is a medical treatment approach that combines elements of phototherapy and immunotherapy to target and treat specific cells or tissues in the body. The key components of this...

A technique used for noncontact inspection of semiconductor wafers. The material is illuminated by an excitation source that stimulates photoluminescence; the resulting spectrum is analyzed, yielding...

Photoluminescence is a phenomenon in which a material absorbs photons (light) at one wavelength and then re-emits photons at a longer wavelength. This process occurs when electrons in the material...

A photomultiplier tube (PMT) is a highly sensitive vacuum tube that detects and amplifies low levels of light. It is widely used in various applications where high sensitivity, fast response times,...

The induction of an electric field in a semiconductor by an incident laser beam. The technique has rapid response time at room temperature.

Photonic crystals are artificial structures or materials designed to manipulate and control the flow of light in a manner analogous to how semiconductors control the flow of electrons. Photonic...

A photonic engine refers to a device or system that utilizes photonics, or the science and technology of generating, controlling, and detecting photons (particles of light), to perform various...

Photoplethysmography (PPG) is a non-invasive optical technique used to detect changes in blood volume in tissues. It measures variations in light absorption caused by the pulsatile nature of blood...

A camera equipped with angular scales in altitude and azimuth. The scale readings are imprinted on the film when an exposure is made. The exact point indicated by the scale readings is shown by...

Phototheranostics, a portmanteau of "photo" (light), "therapy," and "diagnostics," refers to an emerging field that combines therapeutic and diagnostic capabilities in a single platform, often...

Phototherapy is a medical treatment that involves the use of light to treat various conditions, particularly those related to the skin or mood disorders. There are different types of phototherapies,...

A phototransistor is a type of semiconductor device that converts light energy into electrical signals. Similar to a regular transistor, it consists of a semiconductor material (such as silicon) with...

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.

Piezoelectric motion systems are mechanical systems that utilize piezoelectric materials to generate controlled motion or displacement. Piezoelectric materials exhibit the piezoelectric effect, which...

Piezoresistance is a phenomenon in materials science and physics where the electrical resistance of a material changes in response to applied mechanical stress or strain. This change in resistance...

A PIN photodiode is a type of photodetector or semiconductor device used to convert light signals into electrical signals. The name "PIN" is derived from the arrangement of the three semiconductor...

Pitch for polishing mixed with other materials to give it the right viscosity so that it will follow the fine-ground lens surface and yet maintain contact at all times.

Pixel binning, also known as pixel merging or pixel combining, is a technique used in digital imaging and camera technology. It involves the combining or grouping of adjacent pixels on an image...

Plasmon ion-assisted deposition (PIAD) is a technique used in thin-film deposition processes, particularly in the production of optical coatings. This method combines two key processes: plasmon...

A lens made from transparent plastic material. Lenses over 31/2 in. in diameter are usually machined, ground and polished. Smaller lenses are usually injection molded, the mount surrounding the lens...