Collection: UV measuring devices

According to DIN 5031, Part 7,[3] the ultraviolet spectrum encompasses wavelengths from 100 nm to 380 nm (border to visible light), and the frequency of the radiation ranges from approximately 790 THz (380 nm) to 3000 THz (100 nm). The "non-round number" of 380 nm, often used as a limit instead of 400 nm, is defined by the (in)sensitivity range of the eye. UV is therefore, by definition, invisible to the human eye. This range is divided into the sub-ranges UV-A, UV-B, and UV-C. Independent of the DIN standardization, several overlapping and not precisely defined subdivision patterns exist. Especially for the biological and dermatological fields, these include, for example, extreme ultraviolet and vacuum ultraviolet radiation. According to the World Health Organization (WHO), the UV range ranges from 1 nm to 400 nm.[5]

In photolithography (KrF excimer lasers with a wavelength of 248 nm) and laser technology, the term "deep ultraviolet" (DUV) is commonly used for UV radiation with wavelengths below 300 nm. Below 200 nm, ultraviolet radiation is so short-wave and energetic that it is absorbed by molecular oxygen (O2). In the process, the molecular oxygen (O2) is split into two free oxygen radicals (2 O•), each of which reacts further with another molecule of oxygen (O2) to form ozone (O3). UV radiation with wavelengths below 200 nm can therefore only propagate over significant distances under a protective gas, and the short-wave components below 100 nm can only propagate in a vacuum; this is where the term "vacuum ultraviolet" comes from.