The metrological subject field photometry & radiometry is divided into four subfields: photometry, radiometry, colorimetry and fibre optics.

Photometry is concerned with measurements of light related to the way the human eye responds to light. The visible spectrum is thus weighted by a spectral response, which is an approximation to spectral response of the human eye. Photometry deals mainly with the measurement of room light, displays, control panels, streetlights etc. The fundamental unit of visible light is the lumen (lm), the unit of luminous flux. Radiometry is mainly concerned with radia-tion from the electromagnetic spectrum in the range 200 to 20000 nm and with measuring the radiant power (W), radiance (Wsr-1m-2) and radiant energy (J).

Radiometric measurements find increased use in the industrial, health and environmental sectors. Colorimetry deals with the measurement of col-ours, and can be performed after three prescribed methods. Colour measurements play an important role in industry, since the colour of a product plays an important role for the customer. The metrological field of fibre optics covers optical measurements on the optical fibres themselves, fibre optical components and transmission systems. Optical fibres are increasingly used in homes and industry.

DFM is a DANIAmet-NMI in optical radiometry.

Optical radiometry at Danish Fundamental Metrology A/S

DFM maintains a primary standard and working standards for the fundamental radiometric parameter radiant power (W). DFM offers calibration of power metres and detectors operating in the visible and near-infrared (optical fibre) spectral ranges. See more here

Fibre Optics at Danish Fundamental Metrology A/S

DFM offers calibration of fibre optic attenuators. In addition wavelength calibrations of optical spectrum analysers, wavelength metres and lasers are offered, with traceability to the molecular reference lines. See more here


Jan C. Petersen

Danish Fundamental Metrology
Matematiktorvet 307
DK-2800 Kongens Lyngby
Phone: +45 45 25 5864
Fax: +45 45 93 1137