Glossary
A
- Abbe condenser
- A simple condenser lens design that provides some correction for spherical aberration but not chromatic aberration.
- See also: condenser
- aberration
- This term encompasses a variety of irregularities that cause optical performance to deviate from the ideal.
- Synonyms: optical aberration
- See also: astigmatism, chromatic aberration, coma, curvature of image field, distortion, spherical aberration
- achromat objective
- An objective lens that is corrected for axial chromatic aberration at two wavelengths (in the red and blue) and not corrected for field curvature.
- Synonyms: achromatic lens
- See also: objective lens, chromatic aberration, axial chromatic aberration, curvature of field, plan objective, plan achromat objective
- achromatic condenser
- A condenser lens corrected for axial chromatic aberrations at two wavelengths (in the red and blue) and not corrected for spherical aberration.
- See also: condenser, aplanatic condenser, achromatic-aplanatic condenser, chromatic aberration, axial chromatic aberration, spherical aberration
- achromatic doublet
- A pair of lenses made of glasses of with different dispersion properties that are combined to correct for axial chromatic aberration at two wavelengths (in the red and blue).
- See also: achromat objective, objective lens
- achromatic lens
- see achromat objective
- achromatic-aplanatic condenser
- A condenser lens corrected for both axial chromatic aberrations at two wavelengths (in the red and blue) and spherical aberration.
- See also: condenser, chromatic aberration, spherical aberration
- acousto-optic deflector
- see acousto-optic modulator
- acousto-optic modulator (AOM)
- A device that uses the acousto-optic effect to modulate the diffraction of light, commonly used to control the direction and intensity of laser light.
- Synonyms: Bragg cell, acousto-optic deflector
- See also: acousto-optic tunable filter
- acousto-optic tunable filter (AOTF)
- A device that uses the acousto-optic effect to modulate the diffraction of light and is commonly used to select laser lines and adjust their intensity in a confocal system.
- See also: acousto-optic modulator
- air objective
- see dry objective
- Airy beam
- A type of propagation invariant beam that has been applied in light sheet fluorescence microscopy to extend the usable field of view.
- See also: Gaussian beam, Bessel beam, light sheet fluorescence microscopy
- Airy disc
- see Airy disk
- Airy disk
- The circular intensity maximum at the center of an Airy pattern, which is the diffraction pattern formed when imaging a point source.
- Synonyms: Airy disc
- See also: Airy pattern, perfect lens, diffraction, interference, superposition principle, point-spread function, diffraction pattern, spatial resolution
- Airy pattern
- A diffraction pattern consisting of a central circular maximum surrounded by a series of concentric rings of decreasing intensity formed when imaging a point source.
- See also: Airy disk, perfect lens, diffraction, interference, superposition principle, point-spread function, diffraction pattern, spatial resolution
- Airy unit (AU)
- The diameter of the Airy disk, measured trough-to-trough, with a distance of 1 AU often recommended as the optimal pinhole diameter in a confocal system.
- See also: Airy disk, Airy pattern, confocal microscopy, pinhole, optical sectioning, numerical aperture
- aliasing
- When a signal is sampled below the minimum Nyquist sampling frequency, resulting in image artifacts such as Moiré patterns.
- See also: Nyquist sampling
- amplitude point-spread function (APSF)
- The impulse response of a coherent imaging system. It forms a Fourier Transform pair with the system's amplitude transfer function. The square of the amplitude point-spread function is the intensity point-spread function of an incoherent imaging system.
- Synonyms: amplitude-spread function, coherent spread function
- See also: point-spread function, intensity point-spread function, coherent imaging system, pupil function, Fourier transform
- amplitude transfer function (ATF)
- The Fourier transform of the amplitude point-spread function (PSF), it is also the transfer function for a coherent imaging system. The ATF and the Pupil Function are essentially the same, but by convention the Pupil Function is dimensionless and normalized to a value between 0 and 1.
- Synonyms: coherent transfer function
- See also: amplitude point-spread function, optical transfer function, coherent imaging system, modulation transfer function, pupil function
- amplitude-spread function
- see amplitude point-spread function
- analog image
- An image captured on a non-digital medium, such as film, where the signal is not binned into discrete pixels or intensities.
- See also: image, digital image
- analyzer
- A linear polarizer located in the detection optics of polarized light microscopes. It is usually oriented in a north-south (N-S) direction, perpendicular to the orientation of the polarizer in the illumination optics (E-W).
- See also: polarizer, polarized light microscope, crossed polarizers
- angle of incidence
- The angle with which a ray of light is incident on a surface with respect to the normal at the point of incidence.
- See also: refraction, reflection
- angle of view
- The angle between a pair of rays originating from opposite edges of the field of view and crossing at the exit pupil of the microscope.
- See also: field of view
- angular aperture
- The angle between the optical axis and the most oblique light rays captured by the objective lens.
- See also: numerical aperture, solid angle, f-number
- angular size
- see visual angle
- anisotropy
- Description for a material having different structural characteristics when measured in different directions, resulting in the refractive index varying based on the view.
- See also: birefringence, refractive index, polarized light microscopy
- apertometer
- A type of device used to evaluate the angular aperture of a microscope or other optical component.
- See also: angular aperture
- aperture
- The area of a lens or mask in an optical system that allows for the passage of light. The aperture of an objective lens defines its numerical aperture and is considered the imaging aperture of the optical system.
- See also: angular aperture, iris diaphragm, pupil, diaphragm, imaging aperture, numerical aperture
- aperture diaphragm
- see aperture stop
- aperture plane
- One of the conjugate set of planes present in a microscope optical train that include the light source, aperture stop, objective back focal plane, and other locations.
- See also: field plane, conjugate planes, aperture stop
- aperture stop (AS)
- A diaphragm located in an aperture plane, which is often an adjustable iris diaphragm.
- Synonyms: aperture diaphragm
- See also: field stop, iris diaphragm
- aplanatic
- A lens or lens system with corrections for spherical aberration and coma.
- See also: aplanatic condenser
- aplanatic condenser
- A condenser featuring optical corrections for spherical aberration and coma.
- See also: condenser, aplanatic, achromatic-aplanatic condenser, spherical aberration
- apochromat objective
- An objective lens that is corrected for axial chromatic aberration at three wavelengths and spherical aberration at two wavelengths.
- See also: achromat objective, fluorite objective, chromatic aberration, spherical aberration, objective lens
- apodized dark high phase contrast objective (ADH)
- An apodized phase contrast objective where phase objects appear dark against a light background.
- See also: phase contrast, apodized phase contrast
- apodized dark low phase contrast objective (ADL)
- An apodized phase contrast objective where phase objects appear dark against a light gray background.
- See also: phase contrast, apodized phase contrast
- apodized dark medium phase contrast objective (ADM)
- An apodized phase contrast objective where phase objects appear dark against a medium gray background.
- See also: phase contrast, apodized phase contrast
- apodized phase contrast
- A variation of phase contrast that features rings of neutral density film on either side of the phase film in the detection phase plate to help attenuate halo artifact.
- See also: phase contrast, apodized dark high phase contrast objective, apodized dark low phase contrast objective, apodized dark medium phase contrast objective
- area detector
- A detector array composed of multiple detector elements (pixels), as utilized by digital cameras.
- See also: camera
- areal magnification
- see lateral magnification
- array-scanning confocal microscopy
- A class of confocal microscopy where the sample is scanned by an array of confocal apertures (e.g., spinning disk confocal microscopy).
- See also: confocal microscopy, confocal, spinning disk confocal microscopy
- artificial intelligence (AI)
- Computational technologies that mimic human learning and decision-making to train for tasks for which they're not explicitly programmed. AI includes the fields of machine learning and deep learning, which rely on artificial neural networks inspired by the connections of neurons in our brains.
- See also: deep learning, training (machine learning)
- artificial neural network (ANN)
- A type of network architecture inspired by the arrangement of neurons in our brain, where each neuron (node) receives input via weighted connections to other nodes and has a certain activation function.
- Synonyms: neural network, neural net
- See also: artificial intelligence, deep learning
- asphere
- see aspherical lens
- aspheric lens
- see aspherical lens
- aspherical lens
- A lens with an aspherical (not circular) surface profile on one or both surfaces, useful for reducing optical aberrations.
- Synonyms: asphere, aspheric lens
- See also: lens
- assisted reproductive technology (ART)
- General term for the family of fertility technologies including in vitro fertilization (IVF).
- See also: in vitro fertilization, intracytoplasmic morphologically selected sperm injection, intracytoplasmic sperm injection
- astigmatism
- A type of optical aberration where light propagating along two perpendicular planes is brought into sharp focus at two different points along the optical axis.
- See also: aberration
- attenuation coefficient
- see extinction coefficient
- auto correction collar (ACC)
- A microscope objective correction collar (used for minimizing spherical aberration) with a motorized adjustment mechanism.
- See also: correction collar, spherical aberration, correction
- autofluorescence
- Fluorescence arising from the excitation of naturally fluorescent components occurring in the object.
- Synonyms: primary fluorescence
- See also: fluorescence
- autofocus (AF)
- A general term for different approaches to keep an object in focus. It is perhaps used most often in reference to software-based autofocusing, where the sample or objective lens positioned is based on the defocus detected in the image.
- See also: focus
- avalanche photo diode (APD)
- A semiconductor photodiode detector that uses the photoelectric effect to convert incident light into an electrical signal for detection.
- See also: single-photon avalanche diode array
- averaging
- The averaging of multiple images frames in order to reduce Poisson noise in the data.
- See also: line averaging, frame averaging, confocal microscopy
- axial chromatic aberration
- Chromatic aberration arising from the wavelength dependence of refraction - different colors are focused to different points along the optical axis in uncorrected lenses.
- Synonyms: chromatic distortion
- See also: aberration, lateral chromatic aberration
- axial illumination
- Illumination with a ray bundle traveling parallel to the optical axis.
- axial magnification
- Magnification occurring along the optical axis (in the Z directions). It is equal to the square of lateral magnification divided by the refractive index of the immersion medium.
- Synonyms: longitudinal magnification, Z magnification
- See also: aberration, axial chromatic aberration, magnification, lateral magnification, refractive index, immersion medium
- axial resolution
- Optical resolution in the Z (axial) directions.
- Synonyms: longitudinal resolution
- See also: resolution, spatial resolution
