Predictable Quantum Efficient Detector (PQED)

MRI and MIKES collaborated in a workpackage of a European project (http://www.quantumcandela.net/) that achieved a significant improvement in the measurement uncertainty of optical power using a special silicon-based photodiode (Predictable Quantum Efficient Detector, PQED). The PQED photodiodes are fabricated from low-doped p-type silicon, which ensures that the loss mechanisms of charge carriers are almost completely eliminated. The PQED is the first detector with predictable quantum efficiency equal to unity within 80 ppm (parts per million) standard uncertainty at room temperature. It achieves that uncertainty over the whole visible wavelength range, when a reverse bias voltage of 5 V is used. Earlier such low uncertainty could be achieved only with a voluminous cryogenic radiometer operated close to the temperature of liquid helium (about –250 °C).

When the PQED was cooled to liquid nitrogen temperature (about –200 °C), the same quantum efficiency as at the room temperature was reached, even without the reverse bias voltage. The advantage of low-temperature operation is that the quantum efficiency can be predicted theoretically with less than 10 ppm uncertainty. The challenge of future research is to validate the latter uncertainty.

The PQED operated at room temperature will become available from a Finnish measurement technology company Fitecom Oy. The advantage of the PQED as a primary standard is that the realisation of the optical power unit is much easier with a room temperature device than with a cryogenic radiometer cooled to liquid helium temperature.

Contact person

Farshid Manoocheri
farshid.manoocheri(at)aalto.fi

Project pictures

Figure 1. PQED photodiode fabricated by VTT, Finland. The active area is 11 mm x 22 mm.

Figure 2. PQED liquid nitrogen cryostat and Meelis Sildoja in a clean room.

Figure 3. Structure of the PQED. The reflected intensity is between 10 and 70 ppm of the incident intensity.

Related material

  • M. Sildoja, F. Manoocheri and E. Ikonen, “Reflectance calculations for predictable quantum efficient detector,” Metrologia 46, S151–S154 (2009).
  • J. Gran, T. Kübarsepp, M. Sildoja, F. Manoocheri, E. Ikonen, and I. Müller, “Simulations of predictable quantum efficient detector with PC1D, Metrologia 49, S130-S134 (2012).
  • E. Ikonen “Silicon photodiodes as efficient detectors of light,” Proceedings of the Northern Optics 2009 Conference, Vilnius, Lithuania, August 26–28, 2009, p. 30 (invited talk).
  • E. Ikonen, A. Haapalinna, M. Sildoja and F. Manoocheri, “Photon-to-electron converter with 1 ppm quantum deficiency,” Proceedings of the Northern Optics 2009 Conference, Vilnius, Lithuania, August 26–28, 2009, p. 114 (poster).
  • E. Ikonen, A. Haapalinna, M. Sildoja, and F. Manoocheri, “Photon-to-electron converter with 1 ppm quantum deficiency,” Proceedings of Metrology Symposium 2010, (Queretaro, Mexico, October 2010) CD, 2 p. (invited talk).
  • F. Manoocheri, M. Sildoja, M. Merimaa, E. Ikonen, I. Müller, L. Werner, J. Gran, S. S. Hoem, T. Kübarsepp, G. Porrovecchio, M. Smid, G. Brida, and M. L. Rastello, Predictable Quantum Efficient Detector (PQED), Proceedings of NEWRAD 2011 Conference (Hawaii, USA, 2011) pp. 13-15. (invited talk) available at http://newrad2011.org/program.php or http://newrad2011.aalto.fi/
  • M. Sildoja, F. Manoocheri, M. Merimaa, E. Ikonen, I. Müller, L. Werner, J. Gran, T. Kübarsepp, M. Smid, and M. L. Rastello, Predictable Quantum Efficient Detector I: Photodiodes and Design, Proceedings of NEWRAD 2011 Conference (Hawaii, USA, 2011) pp. 227-228.
  • I. Müller, G. Brida, J. Gran, S. S. Hoem, E. Ikonen, T. Kübarsepp, U. Linke, F. Manoocheri, M. Sildoja, M. Smid, L. Socaciu-Siebert, and L. Werner, Predictable Quantum Efficient Detector II: Characterization Results, Proceedings of NEWRAD 2011 Conference (Hawaii, USA, 2011) pp. 209-210.
  • S. S. Hoem, J. Gran, M. Sildoja, F. Manoocheri, E. Ikonen, and I. Müller, Physics of Self-Induced Photodiodes, Proceedings of NEWRAD 2011 Conference (Hawaii, USA, 2011) pp. 259-260.
  • J. Gran, T. Kübarsepp, M. Sildoja, F. Manoocheri, E. Ikonen, and I. Müller, Simulations of Predictable Quantum Efficient Detector with PC1D, Proceedings of NEWRAD 2011 Conference (Hawaii, USA, 2011) pp. 263-265.
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