Research and development

Metrosert participates in international research and development activities and carries out R&D projects in accordance with the specific demands and needs of its customers.


Development and construction of measuring devices

Trap detectors for accurate optical power measurements

At research and development division, we design and construct special photodetectors, so-called trap detectors. Our portfolio includes production of reflection- and transmission-type detectors consisting of 3, 4, 6 and 10 photodiodes. We use high-quality photodiodes with active area of 10×10 mm2 or 18×18 mm2  assembled in polarisation-independent configuration in the detectors.  The trap detectors have an option of mounting valves to supply dry nitrogen or air flow. We can also provide with stabilised-temperature filter radiometers based on trap detectors.

Our research interests are in studies and applications of trap detectors in ultraviolet (5-element trap detector) and in infrared (2-element trap detectors) wavelength ranges, also.

A three-element photodetector with a protective cap

The optical path of a light beam in a 3-element trap detector

The benefits of multi-photodiode detectors:

  • low reflection/transmittance losses
  • large active area
  • uniform responsivity over active area
  • predictable reflection/transmission in the visible wavelength range

For further information contact us:

A selection of related publications:

  • Toomas Kübarsepp, Petri Kärhä, and Erkki Ikonen, “Characterization of a polarization-independent transmission trap detector,” Appl. Opt. 36, 2807-2812 (1997)
  • Toomas Kübarsepp and Malcolm White, “Ten-element photodetector for optical power and attenuation measurements,” Appl. Opt. 49, 3774-3779 (2010)
  • A. Vaigu et al, Compact two-element transmission trap detector for 1550 nm wavelength, Meas. Sci. Technol., 26, 1-6 (2015)
  • M.M. Sildoja et al, High efficiency five-element trap detector with low optical losses, Journal of Physics: Conference Series, Volume 2149, 14th International Conference on New Developments and Applications in Optical Radiometry (NEWRAD 2021) 21-24 June 2021, NIST, Boulder, USA

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