Photonics Dictionary: P

A photographic camera designed to produce reproduction film of visual information (pictures, line drawings, graphs) for printing purposes.

A lens that is symmetrical and designed to work between 1:1 and about 4:1. It covers a field of about ±20° at f/8 or f/10, and may have a focal length up to about 30 in., although the usual...

A contour mapping technique that involves projection of a grating onto an object to produce a shadow grating that is observed through another grating. Therefore, the size of the object to be measured...

A device used to project a small area of light on a screen for indication.

The measurement of surface temperature by a thermograph that forms a pattern of the heat radiated by the surface on a luminescent screen.

A microscope that uses an extremely fine x-ray focal point to produce an enlarged photographic image of a sample. Also known as an x-ray shadow microscope.

An assembly of prototype instruments, equipment and/or software designed to perform all the functions of a concept or idea which, when operated as a system, produce evidence, results or data...

For an electromagnetic field mode varying sinusoidally with time at a given frequency, the logarithmic rate of change, with respect to distance in a given direction, of the complex amplitude of any...

A film applied to a coated or uncoated optical surface primarily for protecting this surface from mechanical abrasion, from chemical corrosion, or from both. For example, a thin layer of silicon...

A method used to approximate the values of the homogeneous second derivatives at each iteration in the course of lens design and that excels the rate of convergence of the damped least squares method...

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....

The instrument used to analyze a pulsed electromagnetic wave to determine its time, amplitude, duration and shape, and to display this information in some appropriate form, either visually or...

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...

A device designed to detect frequency-modulated signals by forming a unidirectional pulse from each sine wave. The direct current of the pulse is proportional to the frequency of the...

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 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...

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...

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.