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Proposed iMERA Special Facility (Pilot Period)

TULIP (Fig. 1) is a laser based facility for:

  • Spectral irradiance responsivity calibration of detectors with apertures up to 100 cm²
  • Spectral radiance responsivity calibration
  • Stray-light characterisation and calibration of array spectrometers
  • All-purpose tuneable monochromatic optical radiation covering the visible and adjacent UV an NIR spectral ranges

 

 

Fig. 1: TULIP facility for the calibration of detectors

Based on a set of continuous wave and pulsed tuneable lasers (see Fig. 2), uniform wavelength scanning high-irradiance monochromatic radiation fields are produced, where polarisation and speckle effects are suppressed using a combination of light guides, integrating spheres and/or rotating holographic diffusers in the beam path of the lasers.

In the uniform radiation field which can be adapted to the requirements of the investigation under consideration, e.g. using the Lambertian output of different spheres or diffusers and different apertures, calibration of filter detectors and photometers can be performed using appropriate substitution and monitor methods. Currently, calibrated Si trap detectors, traceable back to the cryogenic radiometer of PTB are used as transfer standards.

The link to non-coherent radiation fields at high irradiance levels is provided by a special complementary spectroradiometer setup.

 

 

Fig. 2: Currently and concurrent usable wavelength ranges, which will be extended continuously

Proposed Pilot Projects:

a) Implementation of a broadband cryogenic radiometer within TULIP

     

    • Establishment of direct traceability to a broadband cryogenic radiometer as a primary detector standard
    • Calibration of photometers and filter radiometers against a broadband cryogenic radiometer

b) Stray-light correction of array spectrometers

     

    • Application of pulsed laser radiation for stray-light characterisation of spectrometers using a stray-light correction matrix
    • Absolute calibration of array spectrometers
    • Test of stability and reliability of absolutely calibrated array spectrometers

Partners or external users: NMIs and calibration laboratories

 

 

Selected publications:

  • A. Sperling, O. Larionov, U. Grusemann, S.Winter: Stray-light correction of array spectrometers using tuneable pulsed and cw lasers; Proceedings of the 9th international conference on new developments and applications in optical radiometry (NEWRAD), Davos, 2005, ISBN-10 3-033-00570-5, ISBN-13 978-3-033-00570-9, Davos, p. 93

  • S. Winter, D. Lindner, A. Sperling, G. Sauter, S. Brown, T. Larason, Y. Zong, Y. Ohno: Comparison of photometer calibrations at six different facilities of PTB and NIST; Proceedings of the 9th international conference on new developments and applications in optical radiometry (NEWRAD), Davos, 2005, ISBN-10 3-033-00570-5, ISBN-13 978-3-033-00570-9, p. 243