- Transparency (optics)
optics, transparency (also called pellucidity) is the materialproperty of allowing lightto pass through. In mineralogy, another term for this property is diaphaneity. The opposite property is opacity. Transparent materials are clear: they can be seen through. Translucent materials allow light to pass through them only diffusely: they cannot be seen through. Translucency does not include see-through colored objects such as (for instance) emeraldin its cut state (which is transparent) but does include things such as frosted glasswhich allow light to come through but no distinct images.
Though transparency usually refers to visible light in common usage, it may correctly be used to refer to any type of
radiation. For example, flesh is transparent to X-rays, while bone is not, making X-ray imaging useful for medicine.
Examples of transparent materials are
airand some other gases, liquidsuch as water, most glasses, and plastics such as Perspex. Where the degree of transparency varies according to the wavelengthof the light, the image seen through the material is tinted. This may be due to certain metallic oxide molecules in glass, or larger colored particles, as in a thin smoke. If many such particles are present the material may become opaque, as in thick smoke.
There are transparent
glasswalls that can be made opaque by the application of an electric charge, a technology known as electrochromics.
crystals are transparent because there are straight lines through the crystal structure. Light passes unobstructed along these lines.
There is a theory which predicts the absorption of
photons by a material. See absorption (optics)and absorption spectroscopy.
Electromagnetically induced transparency
List of optical topics
Wikimedia Foundation. 2010.