6,181 terms
Photonics Dictionary
Clear All Filters xTE x
oblique errorThe image error that results from astigmatism, coma, oblique spherical aberration, lateral color and distortion.
oblique illuminationA common technique in microscopy, oblique illumination is one in which the object is illuminated by a light source that is at an oblique angle (on the side) to the optical axis. This technique is...
observatory domeA hemispherical covering that is rotatable about a central axis. There is a slit opening along one side wide enough to allow a telescope to be directed at any vertical angle up to 90°.
occluderA device that completely or partially restricts the amount of light reaching the eye.
OCCRoptical Chinese character recognition
OCDRoptical coherence domain reflectometer
ocean colorRefers to the characteristic hue of the ocean according to the presence and concentration of specific minerals or substances, such as chlorophyll. Atmospheric aberrations of color must be corrected...
OCMoptical countermeasure
OCRoptical character recognition; optical character reader
octaveIn optics, an octave typically refers to a range of frequencies or wavelengths that spans a factor of 2. In other words, when dealing with optics, an octave encompasses a doubling of frequency or...
ocular -> eyepieceAlso known as ocular. The lens system used between the final real image in a visual optical system and eye. It acts as an image magnifier. Many types of eyepieces are known; e.g., the Huygens used in...
ocular accommodationOcular accommodation is the process by which the eye changes its optical power to maintain a clear image (focus) on an object as its distance varies. This process is essential for seeing objects at...
ocular accommodation reflexThe eye's involuntary reaction in the process of accommodation. This reflex is most dramatic in response to looking at a distant object after having previously been focused on a near object or vice...
ocular surfaceThat surface of a lens located nearest to the eye.
OCVoptical character verification
OCWRoptical continuous wave reflectometer
ODoptical density; outside diameter
OEICoptoelectronic integrated circuit
OFDopen-face detector
OFDRoptical frequency domain reflectometer
off-axis paraboloid and ellipsoid mirrorOff-axis paraboloid and ellipsoid mirrors are specialized optical components used in various optical systems, particularly in applications requiring precise focusing, collimation, or imaging of...
off-axis paraboloidal mirror -> paraboloidal mirrorA concave mirror that has the form of a paraboloid of revolution. The paraboloidal mirror may have only a portion of a paraboloidal surface through which the axis does not pass, and is known as an...
offset prismA prism or prism assembly that serves to displace the instrument's optical axis.
ohmThe electrical resistance between two points of a conductor when a constant difference of potential of one volt, applied between these points, produces in this conductor a current of one ampere, the...
OIGoptically isolated gate
oil-immersion objectiveA form of high-power microscope objective where the space between the object and the first element is filled with an oil having the same index as that element. This form reduces losses, increases the...
OISLoptical intersatellite link
OITDAOptoelectronic Industry & Technology Development Association (Japan)
OLCRonline character recognition
oleophobicOleophobic is a term used to describe substances or materials that repel or resist oils. The word oleophobic comes from the Greek words "oleo," meaning oil, and "phobos," meaning fear. Oleophobic...
OLToptical lay-up template; optical line terminator
OLTSoptical loss test set
OMoptical master
OMASoptoelectronic mular assembly system
on-board opticsOn-board optics refers to optical systems integrated into devices or platforms for various purposes, such as imaging, navigation, communication, and sensing. These systems are crucial in a wide range...
ondoscopeA glow discharge tube placed on an insulating rod to detect the presence of high-frequency radiation in the vicinity of a transmitter. The tube indicates the presence of the radiation by the glow...
ONIoptical network interface
OOIopen optical interface
opacityOpacity refers to the degree to which something is not transparent or translucent, meaning that it doesn't allow light to pass through it easily. It's a measure of how much a material obstructs the...
opal glassA material consisting of very small colorless particles imbedded in a clear glass matrix. It is available in two forms: flashed opal and pot opal. The flashed variety consists of a rather thin layer...
opal lampA tungsten filament lamp that uses an opal glass bulb to diffuse light.
opaqueA term describing a substance that is impervious to light; the characteristic of a substance that has no luminous transmittance.
opaque projectorAn opaque projector is a device used for enlarging and projecting images from opaque objects such as printed pages, photographs, or three-dimensional objects onto a screen or surface. Unlike a...
OPDARoptical detection and ranging
open-dish methodA measurement method for reflectance by gas ionization in which light passes through a vapor before and after reflection. Detection is accomplished with a phosphor-tipped lightpipe that leads to a...
ophthalmic instrumentsA family of specialized instruments used by ophthalmologists and optometrists to study a patient's eyes and prescribe spectacles. It includes the ophthalmoscope to observe and photograph the retina;...
ophthalmic photographyThe methods and techniques used to obtain medical photographs of the human eye. To photograph the exterior of the eye, conventional still photographic equipment and procedures are used. Similarly, in...
ophthalmologyOphthalmology is a branch of medicine that focuses on the anatomy, physiology, and diseases of the eyes and visual system. Ophthalmologists are medical doctors who specialize in the diagnosis,...
ophthalmoscopeAlso referred to as a funduscope, an ophthalmoscope is a specialized instrument used by ophthalmologists for observing and photographing the fundus (interior) of the eye which includes the retina,...
ophthalmoscopyAlso referred to as fundus photography, ophthalmoscopy is the dioptrical study of the various interior components of the eye such as the macula, fovea, and opticdisk, and is overall essential in...
Photonics Dictionary