Glossary
Absorption: In a light beam, reduction of intensity or energy in the beam due to conversion of light energy to another form, e.g. heat.
Anisotropy / anisotropic: Referring to a non-uniform spatial distribution of physical or polarimetric properties.1
Birefringence: A difference in the birefringent index of a material that depends on the polarization of light passing through it. Effect includes a change of phase between the s and p polarizations and a change of direction between these two polarizations directions.
Double refraction: The difference of the indices of refraction of the components within the material; see also birefringence.2
Fast axis: The axis of a birefringent material that aligns with the faster moving component of the polarized light as it passes through the sample.2
Fused Silica: A type of non-crystalline glass or silica this is fused into a single structure providing optical and thermal properties that are superior to other types of glass.1
Index of Refraction (refractive index): For an optical material, the ratio of the speed of light in a vacuum to the speed of light in the material.
Intrinsic birefringence: Birefringence in a material that is not induced by any outside forces.
Isotropic: Having the same optical properties in all directions.1
Lithography (optical lithography): A photographic method for creating two dimensional patterns in semiconductor device fabrication in which a photoresist is exposed to light and then developed to create a pattern on a given substrate (generally silicon). This method is similar to conventional lithography as it is used for printing on smooth, flat surfaces. However, optical lithography produces patterns that can be measured on a scale of nanometers while still holding immaculate precision.1,4
Optically isotropic: The index of refraction is equal in all directions throughout the material’s crystalline lattice.2
Phase difference: A difference in the start of the signal cycle between two signals of the same frequency.1
Photonic spectrum (Ultraviolet light, Visible light, Infrared light)
-Ultraviolet light: Subdivided into: Near UV (200-380nm wavelength), Far, vacuum, or deep UV (10–200 nm; abbrev. FUV, VUV, or DUV), and Extreme UV (1–31 nm; abbrev. EUV or XUV).1
-Visible light: Light to which the human eye responds, typically 400 to 700nm.1
-Infrared light: Subdivided into: Near infrared (750nm-3µm; abbrev. NIR), Mid infrared (3-30µm, abbrev. MIR), and Far infrared (30µm-1000µm, abbrev. FIR)1
Plane of incidence: The plane created by the incident beam and surface normal.
Polarimetry: Measurement of optical rotation of a sample.2 See also: Stokes Polarimetry.5
Polarization state: A description of the polarimetric properties of an electromagnetic wave.6
Reflection: The change of direction of a wavefront between two dissimilar media. The angle at which a light beam hits a surface is referred to as the angle of incidence (Ti) and is equal to the angle of reflection(Tr).1
Refraction: The change in the direction of a wave due to a change in velocity. This is most frequently seen when a light source passes from one medium to another.1
Retardation: The integrated effect (on the relative phase) of two orthogonal polarized light beams traveling along a path in a birefringent material.
Slow axis: The axis of a birefringent material that aligns with the slower moving component of the polarized light passing through a sample.
Soleil-Babinet compensator: A continuously adjustable retardation plate.7
Substrate: A catalytic material that is used for chemical species to react upon.1
Waveplate (retarder): An optical device used to shift the phase of a lightwave between two perpendicular polarization components.1
Wavelength: The distance between two repeating points on a wave (i.e. from positive crest to positive crest) that symbolizes one complete cycle of a wave. This is a measurement that is independent of the amplitude as it is a measurement of the direct distance between the two defined points.