Glossary
T
- temporal resolution
- The minimal time interval between imaging frames in a timelapse acquisition running at continuous speed.
- See also: resolution, sampling rate, Nyquist sampling
- temporally coherent illumination
- A wavefront of illumination that does not interfere with itself across various points in time - it maintains a more-or-less constant phase relationship across time and space. It is quantified as the coherence length.
- See also: coherence, spatially coherent illumination, phase, interference
- test object
- A microscope specimen (object) with features that are used as a standard for assessing the performance of an optical system. An historical example is the spacing of frustules on diatoms.
- thin-film filter
- see interference filter
- third harmonic generation microscopy (THG)
- An non-linear optics methodology where three lower energy photons are up-converted to one-third the wavelength (i.e. triple the frequency) of an excitation laser. This phenomenon isn't restricted to non-centrosymmetric materials (as with second harmonic generation), but is strongest at material interfaces.
- Synonyms: frequency tripling
- See also: second harmonic generation microscopy, non-linear optics
- three-photon excitation (3PE)
- Three-photon excitation refers to the excitation of a system by three photons arriving simultaneously and via virtual energy levels, commonly used in multiphoton microscopy. The three-photon excitation wavelength tends to be roughly triple the usual one-photon excitation wavelength.
- See also: multiphoton excitation, one-photon excitation, two-photon excitation, multiphoton microscopy
- tiling
- see image stitching
- time lapse imaging
- An imaging methodology where a sequence of images are taken of the same object (typically a live specimen) at a regular interval, and biological or chemical changes are observed and analyzed.
- tissue clearing
- A sample preparation methodology that imparts a specimen with a high degree of optical transparency. This is typically achieved by homogenizing the refractive indexes of specimen features.
- Synonyms: optical clearing
- See also: refractive index, expansion microscopy
- tissue culture
- The growth in an artificial medium of cells derived from living tissue.
- Synonyms: cell culture
- total internal reflection fluorescence microscopy (TIRF)
- A microscopy technique which harnesses the principles of total internal reflection (TIR), where incident fluorescent light at high enough angles reflects off of the interface between the coverslip and the immersion media/specimen, but also resulting in an evanescent wave shallowly penetrating the sample. This provides a very high degree of optical sectioning about the interface.
- See also: fluorescence, fluorescence microscopy, optical sectioning
- total magnification
- The magnification of the objective lens, multiplied by that of any other components in the optical train when forming a real image. For example, a microscope with a 60X objective lens, 10X eyepiece, and 1.5X relay lens provides a total magnification of 900X.
- Synonyms: total magnification of a microscope
- total magnification of a microscope
- see total magnification
- training (machine learning)
- A computational process where a neural network is provided with example inputs and expected outputs, and its weights are adjusted in an iterative process to maximize accuracy.
- See also: artificial intelligence, deep learning
- transmittance
- The percentage of light that successfully passes through (is transmitted) by a given sample. Intensity is often lost to effects such as absorption, reflection, and scattering.
- See also: objective lens spectral transmittance by design, neutral density filter
- transmitted light illumination (diascopic illumination)
- Microscope techniques where illumination light transmitted through the object is collected and detected.
- Synonyms: diascopic illumination
- See also: epi-illumination
- transverse magnification
- see lateral magnification
- trinocular tube
- A microscope observation tube where three optical paths are available: typically two for each eye, and one for a camera.
- See also: observation tube, monocular tube, binocular tube, quadrocular tube
- tube
- Section of microscope between the objective lens and the eyepiece, with the principal component being the body tube found in the microscope base.
- See also: observation tube, body tube, intermediate tube
- tube factor
- The total product of the individual factors of the intermediate lenses in a tube.
- See also: magnification, total magnification
- tube length
- Distances between different planes and surfaces in a tube.
- See also: tube
- tube lens
- see normal tube lens
- tube lens focal distance
- see tube lens focal length
- tube lens focal length
- The focal length of the tube lens, which focuses light gathered by an infinity-corrected objective lens to form an image. Longer tube lens focal lengths allow for additional optical components to be introduced to the light path.
- Synonyms: tube lens focal distance
- See also: tube lens, focal length, infinity optical system
- tungsten-halogen lamp
- see halogen lamp
- two-beam interference
- The superposition and interference of two similar waves according to the superposition principle.
- See also: interference, superposition principle
- two-photon excitation (2PE)
- Two-photon excitation refers to the excitation of a system by two photons arriving simultaneously and via a virtual energy level, commonly used in multiphoton microscopy. The two-photon excitation wavelength tends to be roughly twice the usual one-photon excitation wavelength.
- See also: multiphoton excitation, one-photon excitation, three-photon excitation, multiphoton microscopy
