Photonics Dictionary: P

An accurately produced hole of any size and shape that is used as a masking device in an optical system. Pinhole apertures of accurate diameters often are produced by laser beam penetration or by...

Characteristic of optical analyses that are limited to infinitesimally small apertures. Also called first-order or Gaussian optics.

Two simple meniscus lenses arranged symmetrically on either side of the aperture stop, providing reduced coma, lateral color and distortion.

A high-speed, narrow-field lens consisting of two achromats spaced about the aperture stop. Its uses include portrait photography and motion picture projection.

In optics and photolithography, a phase mask refers to a device that modifies the phase of light waves passing through it. The phase mask is used to control the spatial distribution of the light's...

The propagation or hindrance of waves reaching each aperture of the interferometer because of atmospheric turbulence.

A lensless photographic camera that uses a small sharp-edged hole as its aperture. The light passed by this aperture onto the camera's film plane produces a soft-edged image that has a wide field of...

The direct cladding used for fused silica cores to create large numerical aperture fibers and used as overcoats to glass-clad fibers to reduce microbend loss and increase mechanical protection.

A lamp, usually incandescent, that has a very compact filament, permitting a greater concentration of emitted light, aided by the use of small apertures and appropriate reflectors.

Coded image obtained optically with a nonredundant pinhole array imaging aperture.

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...

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.