In optics, the term dichroic has two related but distinct meanings. A dichroic material is one which either causes light to be split up into distinct beams of different wavelengths (colours), or, one in which light rays having different polarizations are absorbed by different amounts. Optics (appearance or look in ancient Greek) is a branch of physics that describes the behavior and properties of light and the interaction of light with matter. ... The wavelength is the distance between repeating units of a wave pattern. ... Color is an important part of the visual arts. ... This article treats polarization in electrodynamics. ...

The original meaning of dichroic (from the Greek dikhroos, two-coloured) refers to any optical device which can split a beam of light into two beams with differing wavelengths. Such devices include mirrors and filters, usually treated with optical coatings, which are designed to reflect light over a certain range of wavelengths, and transmit light which is outside that range. An example is the dichroic prism, used in some camcorders, which uses several coatings to split light into red, green and blue components for recording on separate CCD arrays. This kind of dichroic device does not usually depend on the polarization of the light. The term dichromatic is also used in this sense. A mirror is a reflective surface that is smooth enough to form an image. ... Halogen light bulb capsule (center) with an integrated dichroic reflector. ... An optical coating is a thin layer of material placed on an optical component such as a lens or mirror which alters the way in which the optic reflects and transmits light. ... A dichroic prism is a prism that splits light into two beams of differing wavelength (colour). ... 8mm Camcorder mini-DV Camcorder Sony DV Handycam A camcorder is a portable electronic device (generally a digital camera) for recording video images and audio onto a storage device. ... A specially developed CCD used for ultraviolet imaging in a wire bonded package. ...

The second meaning of dichroic refers to a material in which light in different polarisation states travelling through it experience a varying absorption. The term came about because of early observations of the effect in crystals such as tourmaline. In these crystals, the strength of the dichroic effect varies strongly with the wavelength of the light, making them appear to have different colours when viewed with light having differing polarisations. (This is more generally referred to as pleochroism, and the technique can be used in mineralogy to identify minerals). In some materials, such as herapathite (iodoquinine sulfate) or Polaroid sheets, the effect is not strongly dependent on wavelength, and so the term dichroic is something of a misnomer, but still used. Absorption has a number of meanings: In physics, absorption is a process in which particles of some sort encounter another material and are taken up by or even disappear in it. ... Quartz crystal A crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ... The tourmaline mineral group is chemically one of the most complicated groups of silicate minerals. ... Pleochroism is an optical phenomenon where due to double refraction of light by a colored gem or crystal, the light is divided into two paths which are polarized at a 90° angle to each other. ... Mineralogy is an earth science that involves the chemistry, crystal structure, and physical (including optical) properties of minerals. ... Herapathite, or iodoquinine sulphate, is a compound whose crystals are dichroic and thus can be used for polarizing light. ... Polaroid® (a trademark of the Polaroid Corporation) is the name of a type of synthetic plastic sheet which is used to polarise light. ...

Optically active molecules exhibit differing absorption to light of opposite circular polarization. This is known as circular dichroism. When polarized light is passed through a substance containing chiral molecules (or nonchiral molecules arranged asymmetrically), the direction of polarization can be changed. ... In electrodynamics, circular polarization of electromagnetic radiation is a polarization such that the tip of the electric field vector, at a fixed point in space, describes a circle as time progresses. ... Circular dichroism, or CD, is defined as the differential absorption of left and right hand circularly polarized light. ...

Which meaning of dichroic is intended can usually be inferred from the context. A mirror, filter, or beam splitter is referred to as dichroic in the colour-separating first sense; a dichroic crystal or material refers to the polarization-absorbing second sense. A beam splitter is an optical device, that splits a beam of light in two. ...