Glossary

U

ultramicroscopy
see light sheet fluorescence microscopy
ultraviolet microscope
A microscope designed to image specimens using ultraviolet (UV) light.
See also: ultraviolet radiation
ultraviolet radiation (UV)
A type of electromagnetic radiation that has a shorter wavelength than visible light but a longer wavelength than X-rays. This is typically defined to be in the rage of 10 - 400 nm.
See also: radiation, electromagnetic (em) spectrum
undercorrection
A scenario where the objective correction collar is not properly adjusted, which induces spherical aberration with rays converging prior to the expected focus in the image space.
See also: overcorrection, spherical aberration, coverslip correction
undersampling
A property in signal analysis where the sampling rate is less than the Nyquist rate necessary for resolving the underlying signal.
See also: sampling, sampling rate, Nyquist sampling, oversampling
uniaxial material
Anisotropic materials (commonly those with crystalline structure) that are birefringent and feature a single optic axis.
See also: birefringence, polarized light, polarized light microscopy, anisotropy
universal condenser
A microscope condenser assembly that allows a user to perform a multitude of illumination techniques, such as brightfield, darkfield, phase contrast, and differential interference contrast (DIC).
See also: condenser
universal stage
A type of microscope stage that is fully rotatable and can also be tilted at different angles, especially useful for applications in polarized light microscopy.
See also: stage, polarized light microscopy, rotating stage
upright microscope
A microscope in which the objective lens is located above the sample. This is the classic microscope design used for observing microscope slide-mounted specimens.
See also: inverted microscope, microscope
useful magnification range
The total magnification that is helpful for resolving specimen features without spreading out the signal too much. More magnification than useful, termed "empty magnification," occurs when the total magnification results in oversampling of object features well beyond that defined by the Nyquist sampling rate.
See also: empty magnification, oversampling, Nyquist criterion
user interface (UI)
A software interface supporting user interaction. In the context of microscopy software, it is used to capture, analyze, visualize, and otherwise manipulate microscopy images.