Glossary

E

elastic scattering
Scattering where no energy is ultimately transferred to the scattering material.
See also: inelastic scattering, Rayleigh scattering, Mie scattering
electro-optic effect
The sensitivity of a material's refractive index to an electric field. With the Pockels effect, the change in refractive index is proportional to the electric field strength.
See also: refractive index
electromagnetic (em) spectrum
see ultraviolet radiation
electromagnetic spectrum (EM)
The full range of frequencies and types of electromagnetic radiation, from radio waves to gamma rays.
See also: radiation
electron multiplying charge coupled device (EMCCD)
A specialized type of charge coupled device (CCD) detector that additionally features an electron multiplication (EM) register prior to readout, useful for amplifying low signals above the read noise level.
See also: charge coupled device, camera, area detector
electrophysiology
Physiology discipline concerned with the electrical properties of biological systems. The patch-clamp technique allows for studies on the scale of single cells to ion channels, usually with the assistance of a microscope.
elliptically-polarized light
Polarized light where the X and Y components (eigenpolarizations) are out of phase and by a value different than a quarter wavelength.
See also: polarized light, circularly-polarized light, linearly-polarized light
emission
When an excited system releases radiant energy in order to relax to a lower energy state. This term is often used in reference to fluorescence, where a molecule in a higher singlet electronic state emits light in order to relax.
See also: excitation, fluorescence, inelastic scattering, emission filter, fluorophore
emission filter
An optical filter allowing the passage of a certain color or waveband of light and located in the detection optics prior to the detector.
Synonyms: emitter filter, barrier filter
See also: barrier filter, broad-bandpass filter, excitation filter
emitter filter
see emission filter
empty magnification
Magnification beyond which additional detail is no longer apparent (oversampling significantly in excess of the Nyquist sampling rate), sacrificing field of view without increasing resolution.
See also: magnification, Nyquist sampling, oversampling
enhanced resolution (NIS-Elements) (ER)
A deconvolution-based module for the NIS-Elements software designed to maximize the resolution of images acquired using conventional point-scanning confocal microscopes/detectors.
See also: confocal microscopy, deconvolution, point-scanning confocal microscopy
entrance pupil of the microscope
see microscope entrance pupil
epi-illumination
Illumination of the object from the same side that will be used to detect light from the object - usually performed using the same objective lens.
Synonyms: episcopic illumination
See also: epi-illuminator
epi-illuminator
The microscope component used for introducing illumination light to the optical train prior to the objective lens, which also acts as the condenser.
Synonyms: episcopic illuminator
See also: epi-illumination
epifluorescence microscope
see fluorescence microscopy
episcopic illumination
see epi-illumination
episcopic illuminator
see epi-illuminator
episcopic microscope
see reflected-light microscope
excitation
Stimulation of a system to a higher energy state. This term is often used in reference to fluorescence, where light is used to excite a system to a higher singlet electronic state from which it emits fluorescence to relax.
See also: emission, fluorescence, inelastic scattering
excitation filter
An optical filter allowing the passage of a certain color or waveband of light and located in the illumination optics prior to the object.
Synonyms: exciter filter
See also: excitation, excitation waveband, excitation wavelength, fluorescence
excitation waveband
The band of wavelengths (waveband) used for illumination, usually in reference to the illumination light in fluorescence microscopy.
See also: excitation, excitation filter, excitation wavelength
excitation wavelength
This term is usually used in the context of fluorescence microscopy, where it refers to either an excitation waveband or specific excitation wavelength (especially when using monochromatic sources such as lasers).
See also: excitation, excitation filter, excitation waveband
exciter filter
see excitation filter
exit pupil of the microscope
see microscope exit pupil
expansion microscopy (ExM)
A super-resolution microscopy technique predicated on mechanically enlarging a sample via embedding in a swellable hydrogel to provide a de facto increase in resolution during subsequent observations.
Synonyms: magnified analysis of proteome
See also: super-resolution
exposure
The amount of light (signal) that is collected by the detector.
See also: image, detector
extended depth of field microscopy (EDoF)
A collective term for varied approaches to extending the effective depth of field of a microscope system while minimizing tradeoffs such as lower resolution.
See also: depth of field, depth of focus, extended depth of focus image
extended depth of focus image (EDF)
A fully focused composite image created using different approaches for computationally combining a stack of partially in-focus images acquired at different Z planes.
See also: depth of field, depth of focus, extended depth of field microscopy
external diaphragm eyepiece
see Ramsden eyepiece
extinction
Condition that occurs in a polarized light microscope with crossed polarizers where polarized light rays that traveled through an object without a change in their polarization are mostly blocked by the analyzer, resulting in a dark appearance.
See also: polarization, crossed polarizers, extinction ratio
extinction coefficient
As commonly used in the context of fluorescence, it is a measure of how well a fluorophore absorbs an incident photon. This determines a fluorophore's overall brightness together with its quantum yield.
Synonyms: molar absorption coefficient, mass extinction coefficient, attenuation coefficient
See also: brightness (fluorophore), quantum yield, fluorescence, fluorophore
extinction ratio
The ratio of the maximum transmission of a linear polarizer (incident light is linearly polarized parallel to transmission axis) to its minimum (light polarized perpendicular to transmission axis).
Synonyms: polarization extinction ratio
See also: extinction, crossed polarizers, polarization
extra-long working distance objective (ELWD)
Objective lens designed with a significantly longer working distance range than typical, with lower numerical aperture (NA) as a tradeoff.
See also: long working distance objective, super-long working distance objective, objective lens
extraordinary ray
A birefringent material will split light incident at a non-zero angle to its optic axis into two rays with orthogonal linear polarization states. The refractive index experienced by one of the rays will vary depending on the angle of incidence - the extraordinary ray.
Synonyms: extraordinary wave
See also: ordinary ray, birefringence, refraction, polarized light, optical indicatrix
extraordinary wave
see extraordinary ray
eye lens
The eyepiece lens or lens system which is closest to the observer's eye.
See also: eyepiece, optical train
eye relief
see eyepoint height
eyepiece
A lens or lens assembly that is inserted into the microscope observation tube and facilitates visual observation of the image.
Synonyms: ocular
See also: microscope, optical train, observation tube, eyepiece field number
eyepiece diopter adjustment
Eyepieces typically come equipped with a rotatable diopter adjustment mechanism that allows for users to correct for focal differences between their eyes and maintain parfocality.
Synonyms: eyepiece focus adjustment
See also: focusing
eyepiece field diaphragm
see eyepiece field stop
eyepiece field number
The diameter of the (usually fixed) eyepiece field stop located at the eyepiece intermediate image plane, it restricts the diameter of the observable field of view.
Synonyms: eyepiece field of view, objective field number
See also: eyepiece, field number, field of view, eyepiece field stop
eyepiece field of view
see eyepiece field number
eyepiece field stop
A (usually fixed) field diaphragm that's typically located inside of the eyepiece and in a conjugate field plane - in this case the same plane as the intermediate image plane. It sets the final constraint on the observable field of view.
Synonyms: eyepiece field diaphragm
See also: eyepiece, conjugate planes, intermediate image plane, field plane, eyepiece field number
eyepiece flange
Locating flange (surface) on an eyepiece for mounting in an observation tube. It is coincident with the eyepiece-locating observation tube flange.
Synonyms: locating flange of eyepiece, eyepiece locating surface
See also: eyepiece, mechanical tube length, eyepiece-locating observation tube flange, locating flange
eyepiece focus adjustment
see eyepiece diopter adjustment
eyepiece locating surface
see eyepiece flange
eyepiece parfocal distance
The distance between eyepiece flange and the intermediate image plane coincident with the eyepiece field stop.
See also: parfocality
eyepiece-locating observation tube flange
Locating flange (surface) on an observation tube for mounting an eyepiece. It is coincident with the eyepiece flange.
Synonyms: viewing tube flange
See also: observation tube, eyepiece, eyepiece flange, locating flange
eyepieces
see magnification of an eyepiece
eyepoint height
The distance between that part of the eyepiece lens closest to the observer and the exit pupil of the microscope/entrance pupil of the observer's eye.
Synonyms: eye relief
See also: eyepiece, optical train