Glossary
B
- back focal plane (BFP)
- The focal plane located at the back of a lens or lens system when considering the direction of light travel. The focal plane located on the other side of the lens from the back focal plane is known as the front focal plane.
- Synonyms: rear focal plane
- See also: focal plane, front focal plane
- background subtraction
- Computational subtraction of background signal from a digital image. The background signal can be estimated using a number of different methods, including the average intensity in a featureless region of interest.
- See also: digital image
- bandpass filter (BPF)
- An optical filter that allows a certain band of wavelengths (passband) to pass while blocking others.
- See also: filter, longpass filter, shortpass filter
- barrel distortion
- Geometric aberration where lateral magnification decreases with increasing distance from the optical axis.
- See also: aberration, distortion, pincushion distortion
- barrier filter
- see emission filter
- beamsplitter (BS)
- An optical component that can separate an incident beam into two or more beams.
- See also: polarizing beamsplitter
- Bertrand diaphragm
- A diaphragm located after the Bertrand lens and used to limit the field of view of the conoscopic image.
- See also: Bertrand lens, diaphragm
- Bertrand lens
- A lens that, when inserted in the optical path, allows for the observation of the aperture set of conjugate planes and, in polarized light microscopy, the conoscopic interference pattern.
- See also: Bertrand diaphragm, aperture plane, conoscopic interference pattern, phase telescope
- Bessel beam
- A type of propagation invariant (self-healing) beam formed using an axicon or annular illumination of the objective back focal plane.
- biaxial material
- Material where each of the three principal axes has a different refractive index.
- binning
- The combination of adjacent pixels in an image into a larger superpixel (pixels can be summed or averaged).
- Synonyms: pixel binning
- See also: camera
- binocular microscope
- A microscope featuring a binocular tube for observation.
- See also: optical train
- binocular tube
- An observation tube delivering light to a pair of eyepieces for visual observation.
- See also: observation tube, optical train
- birefringence
- When an optically anisotropic material has different refractive indices corresponding to its different axes, allowing for incident light to be split into 2 or more beams depending on its polarization and direction of propagation.
- Synonyms: double refraction
- See also: polarized light microscopy, refractive index, anisotropy
- blur circle
- see circle of least confusion
- blur spot
- see circle of least confusion
- body tube
- The optical assembly at the core of the microscope base, it includes the nosepiece and is intermediate between the objective lens and observation tube.
- See also: microscope, optical train
- Bragg cell
- see acousto-optic modulator
- bright medium phase contrast objective (BM)
- A phase contrast objective where phase objects appear bright against a medium gray background (sometimes referred to as negative phase contrast).
- See also: phase contrast, objective lens
- brightfield
- A contrast technique where the zeroth order of light transmitted through or reflected at the object field is detected, showing the specimen against a bright background.
- See also: contrasting technique
- brightness (fluorophore)
- The product of the fluorophore's extinction coefficient and quantum yield.
- See also: fluorescence, fluorophore, quantum yield, extinction coefficient
- brightness (objective lens)
- The brightness of illumination is proportional to the square of the condenser numerical aperture (NA) and brightness of detection is proportional to the square of objective lens NA.
- See also: numerical aperture, objective lens
- Brillouin microscopy
- A technique based on detection of Brillouin scattering to probe the mechanical properties of the sample.
- See also: Brillouin scattering
- Brillouin scattering
- A type of inelastic scattering caused by interaction with phonons (excited vibrational modes in elastic structures).
- See also: inelastic scattering
- broad-bandpass filter
- A bandpass filter allowing a wavelength band greater than 50 nm to pass.
- See also: filter, bandpass filter, longpass filter
- bulb
- The enclosure around the source of radiation, typically made of glass or fused silica.
- See also: lamp, light source, illuminator
