Gigahertz Optik - Light Measurement Solutions

The whole discipline of optical measurement techniques can be roughly subdivided into the two areas of photometry and radiometry.
Radiometry is the measurement of optical radiation in physical quantities in the UV-VIS-IR wavelength range from about 100 nm to 1 mm. Thus, the units of all radiometric quantities are based on watts (W, energy per time = power). According to CIE regulations, symbols for radiometric quantities are denoted with the subscript “e” for “energy”. The most commonly measured radiometric quantities are: Radiant Power Φe, Radiant Intensity Ie, Radiance Le and Irradiance Ee.
Sources of optical radiation, like the sun, can be measured using broadband (polychromatic) or spectral (monochromatic) radiometers. Broadband radiometers do not provide spectral data only the absolute value over a defined spectral region is measured. When this defined spectral function is not absolute or 'flat', i.e. spectral sensitivity is 100% over the entire bandpass of interest and 0% at all other wavelengths, these are known as effective radiometric measurements. A good example of an effective radiometric spectral response is the CIE Erythemal function which defines the 'action spectra' or the human skin's spectral sensitivity to ultraviolet radiation. When the detector is configured to mimic this spectral shape this is called an effective rather than absolute measurement.
The Commission Internationale de l'Eclairage was organized to centralize and disseminate information on all aspects of light and its uses. The CIE has defined many absolute as well as effective spectral functions. Examples of CIE defined absolute functions are UV-C (~100-280nm), UV-B (280-315nm) and UV-A (315-400nm). Other organizations like ICNIRP, International Commission on Non-Ionizing Radiation Protection and the ACGIH, American Conference of Governmental Industrial Hygienists have defined spectral functions for UV, Blue Light and IR health hazard as well.
Typical radiometric applications cover only a finite wavelength range within the total optical spectrum. One of the largest, solar radiometry, only spans from ~ 280 to 4000 nm. The CIE and DIN 5031 Part 7 have defined and separated spectral regions providing frames of reference to help standardize and compare measurements.

Gigahertz-Optik manufactures light detectors for use in combination with optometers and accessories to form complete radiometric measurement systems in the wavelength range from 200 to 1800 nm.

Additional information from our Tutorials section: II.4. Basic radiometric quantities

Additional information from our Products section: Radiometric Light Detectors

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