Abstract

Precision power measurements of terahertz (THz) radiation are required to establish metrological applications in the THz spectral range. However, traceability to the International System of Units (SI) has been missing in the THz region in the past. The Physikalisch-Technische Bundesanstalt (PTB), as the national metrology institute of Germany, determines the spectral responsivity of detectors for THz radiation by using two complementary optical methods: source- and detector-based radiometry. Both approaches have been successfully prototyped, and a pyroelectric THz detector with a well-defined aperture is used to verify the consistency of the two independent calibration methods. These primary investigations led to the design of a new measurement facility for the determination of THz radiant power and the responsivity calibration of THz detectors traceable to the SI.

© 2010 OSA

Full Article  |  PDF Article

References

  • View by:
  • |
  • |
  • |

  1. T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).
  2. A. C. Parr, R. U. Datla and J. L. Gardner, eds., “Optical Radiometry,” Experimental Methods in the Physical Sciences, (Academic Press, San Diego, Ca., 2005) Vol. 41
  3. B. Gutschwager, C. Monte, J. Hollandt, H. Delsim-Hashemi, and O. Grimm, “Calculable blackbody radiation as source for the determination of the spectral responsivity of THz detectors,” Metrologia 46(4), S165–169 (2009).
    [CrossRef]
  4. L. Werner, H.-W. Hübers, P. Meindl, R. Müller, H. Richter, and A. Steiger, “Towards traceable radiometry in the terahertz region,” Metrologia 46(4), S160–164 (2009).
    [CrossRef]
  5. L. Werner, J. Fischer, U. Johannsen, and J. Hartmann, “Accurate determination of the spectral responsivity of silicon trap detectors between 238 nm and 1015 nm using a laser-based cryogenic radiometer,” Metrologia 37(4), 279–284 (2000).
    [CrossRef]
  6. P. Meindl, A. E. Klinkmüller, L. Werner, U. Johannsen, and K. Grützmacher, “New UV spectral responsivity scale of the PTB based on a cryogenic radiometer and an argon plasma arc radiation source,” Metrologia 43(2), S72–S77 (2006).
    [CrossRef]
  7. H.-W. Hübers, S. G. Pavlov, A. D. Semenov, R. Köhler, L. Mahler, A. Tredicucci, H. E. Beere, D. A. Ritchie, and E. H. Linfield, “Terahertz quantum cascade laser as local oscillator in a heterodyne receiver,” Opt. Express 13(15), 5890–5896 (2005).
    [CrossRef] [PubMed]
  8. D. Butler, R. Köhler, and G. Forbes, “Diffraction effects in the radiometry of coherent beams,” Appl. Opt. 35(13), 2162–2166 (1996).
    [CrossRef] [PubMed]
  9. JCGM, 100:2008 “Evaluation of measurement data — Guide to the expression of uncertainty measurement (GUM)”, http://www.bipm.org/utils/common/documents/jcgm/JCGM_100_2008_E.pdf
  10. J. Romero, N. P. Fox, and C. Fröhlich, “Improved comparison of the World Radiometric Reference and the SI radiometric scale,” Metrologia 32(6), 523–524 (1995).
    [CrossRef]
  11. PMOD/WRC, http://www.pmodwrc.ch/pmod.php?topic=wrc

2009 (2)

B. Gutschwager, C. Monte, J. Hollandt, H. Delsim-Hashemi, and O. Grimm, “Calculable blackbody radiation as source for the determination of the spectral responsivity of THz detectors,” Metrologia 46(4), S165–169 (2009).
[CrossRef]

L. Werner, H.-W. Hübers, P. Meindl, R. Müller, H. Richter, and A. Steiger, “Towards traceable radiometry in the terahertz region,” Metrologia 46(4), S160–164 (2009).
[CrossRef]

2008 (1)

T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).

2006 (1)

P. Meindl, A. E. Klinkmüller, L. Werner, U. Johannsen, and K. Grützmacher, “New UV spectral responsivity scale of the PTB based on a cryogenic radiometer and an argon plasma arc radiation source,” Metrologia 43(2), S72–S77 (2006).
[CrossRef]

2005 (1)

2000 (1)

L. Werner, J. Fischer, U. Johannsen, and J. Hartmann, “Accurate determination of the spectral responsivity of silicon trap detectors between 238 nm and 1015 nm using a laser-based cryogenic radiometer,” Metrologia 37(4), 279–284 (2000).
[CrossRef]

1996 (1)

1995 (1)

J. Romero, N. P. Fox, and C. Fröhlich, “Improved comparison of the World Radiometric Reference and the SI radiometric scale,” Metrologia 32(6), 523–524 (1995).
[CrossRef]

Beere, H. E.

Bieler, M.

T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).

Butler, D.

Delsim-Hashemi, H.

B. Gutschwager, C. Monte, J. Hollandt, H. Delsim-Hashemi, and O. Grimm, “Calculable blackbody radiation as source for the determination of the spectral responsivity of THz detectors,” Metrologia 46(4), S165–169 (2009).
[CrossRef]

Fischer, J.

L. Werner, J. Fischer, U. Johannsen, and J. Hartmann, “Accurate determination of the spectral responsivity of silicon trap detectors between 238 nm and 1015 nm using a laser-based cryogenic radiometer,” Metrologia 37(4), 279–284 (2000).
[CrossRef]

Forbes, G.

Fox, N. P.

J. Romero, N. P. Fox, and C. Fröhlich, “Improved comparison of the World Radiometric Reference and the SI radiometric scale,” Metrologia 32(6), 523–524 (1995).
[CrossRef]

Fröhlich, C.

J. Romero, N. P. Fox, and C. Fröhlich, “Improved comparison of the World Radiometric Reference and the SI radiometric scale,” Metrologia 32(6), 523–524 (1995).
[CrossRef]

Grimm, O.

B. Gutschwager, C. Monte, J. Hollandt, H. Delsim-Hashemi, and O. Grimm, “Calculable blackbody radiation as source for the determination of the spectral responsivity of THz detectors,” Metrologia 46(4), S165–169 (2009).
[CrossRef]

Grützmacher, K.

P. Meindl, A. E. Klinkmüller, L. Werner, U. Johannsen, and K. Grützmacher, “New UV spectral responsivity scale of the PTB based on a cryogenic radiometer and an argon plasma arc radiation source,” Metrologia 43(2), S72–S77 (2006).
[CrossRef]

Gutschwager, B.

B. Gutschwager, C. Monte, J. Hollandt, H. Delsim-Hashemi, and O. Grimm, “Calculable blackbody radiation as source for the determination of the spectral responsivity of THz detectors,” Metrologia 46(4), S165–169 (2009).
[CrossRef]

T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).

Hartmann, J.

L. Werner, J. Fischer, U. Johannsen, and J. Hartmann, “Accurate determination of the spectral responsivity of silicon trap detectors between 238 nm and 1015 nm using a laser-based cryogenic radiometer,” Metrologia 37(4), 279–284 (2000).
[CrossRef]

Hollandt, J

T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).

Hollandt, J.

B. Gutschwager, C. Monte, J. Hollandt, H. Delsim-Hashemi, and O. Grimm, “Calculable blackbody radiation as source for the determination of the spectral responsivity of THz detectors,” Metrologia 46(4), S165–169 (2009).
[CrossRef]

Hübers, H.-W.

Johannsen, U.

P. Meindl, A. E. Klinkmüller, L. Werner, U. Johannsen, and K. Grützmacher, “New UV spectral responsivity scale of the PTB based on a cryogenic radiometer and an argon plasma arc radiation source,” Metrologia 43(2), S72–S77 (2006).
[CrossRef]

L. Werner, J. Fischer, U. Johannsen, and J. Hartmann, “Accurate determination of the spectral responsivity of silicon trap detectors between 238 nm and 1015 nm using a laser-based cryogenic radiometer,” Metrologia 37(4), 279–284 (2000).
[CrossRef]

Kleine-Ostmann, T.

T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).

Klinkmüller, A. E.

P. Meindl, A. E. Klinkmüller, L. Werner, U. Johannsen, and K. Grützmacher, “New UV spectral responsivity scale of the PTB based on a cryogenic radiometer and an argon plasma arc radiation source,” Metrologia 43(2), S72–S77 (2006).
[CrossRef]

Koch, M.

T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).

Köhler, R.

Linfield, E. H.

Mahler, L.

Meindl, P.

L. Werner, H.-W. Hübers, P. Meindl, R. Müller, H. Richter, and A. Steiger, “Towards traceable radiometry in the terahertz region,” Metrologia 46(4), S160–164 (2009).
[CrossRef]

P. Meindl, A. E. Klinkmüller, L. Werner, U. Johannsen, and K. Grützmacher, “New UV spectral responsivity scale of the PTB based on a cryogenic radiometer and an argon plasma arc radiation source,” Metrologia 43(2), S72–S77 (2006).
[CrossRef]

Monte, C.

B. Gutschwager, C. Monte, J. Hollandt, H. Delsim-Hashemi, and O. Grimm, “Calculable blackbody radiation as source for the determination of the spectral responsivity of THz detectors,” Metrologia 46(4), S165–169 (2009).
[CrossRef]

T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).

Müller, R

T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).

Müller, R.

L. Werner, H.-W. Hübers, P. Meindl, R. Müller, H. Richter, and A. Steiger, “Towards traceable radiometry in the terahertz region,” Metrologia 46(4), S160–164 (2009).
[CrossRef]

Pavlov, S. G.

Pupeza, I

T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).

Richter, H.

L. Werner, H.-W. Hübers, P. Meindl, R. Müller, H. Richter, and A. Steiger, “Towards traceable radiometry in the terahertz region,” Metrologia 46(4), S160–164 (2009).
[CrossRef]

Ritchie, D. A.

Romero, J.

J. Romero, N. P. Fox, and C. Fröhlich, “Improved comparison of the World Radiometric Reference and the SI radiometric scale,” Metrologia 32(6), 523–524 (1995).
[CrossRef]

Schrader, T.

T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).

Semenov, A. D.

Siegner, U.

T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).

Steiger, A

T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).

Steiger, A.

L. Werner, H.-W. Hübers, P. Meindl, R. Müller, H. Richter, and A. Steiger, “Towards traceable radiometry in the terahertz region,” Metrologia 46(4), S160–164 (2009).
[CrossRef]

Tredicucci, A.

Ulm, G

T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).

Werner, L

T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).

Werner, L.

L. Werner, H.-W. Hübers, P. Meindl, R. Müller, H. Richter, and A. Steiger, “Towards traceable radiometry in the terahertz region,” Metrologia 46(4), S160–164 (2009).
[CrossRef]

P. Meindl, A. E. Klinkmüller, L. Werner, U. Johannsen, and K. Grützmacher, “New UV spectral responsivity scale of the PTB based on a cryogenic radiometer and an argon plasma arc radiation source,” Metrologia 43(2), S72–S77 (2006).
[CrossRef]

L. Werner, J. Fischer, U. Johannsen, and J. Hartmann, “Accurate determination of the spectral responsivity of silicon trap detectors between 238 nm and 1015 nm using a laser-based cryogenic radiometer,” Metrologia 37(4), 279–284 (2000).
[CrossRef]

Appl. Opt. (1)

Frequenz (1)

T. Kleine-Ostmann, T. Schrader, M. Bieler, U. Siegner, C. Monte, B. Gutschwager, J Hollandt, A Steiger, L Werner, R Müller, G Ulm, I Pupeza, and M. Koch, “THz Metrology,” Frequenz 62, 137–148 (2008).

Metrologia (5)

J. Romero, N. P. Fox, and C. Fröhlich, “Improved comparison of the World Radiometric Reference and the SI radiometric scale,” Metrologia 32(6), 523–524 (1995).
[CrossRef]

B. Gutschwager, C. Monte, J. Hollandt, H. Delsim-Hashemi, and O. Grimm, “Calculable blackbody radiation as source for the determination of the spectral responsivity of THz detectors,” Metrologia 46(4), S165–169 (2009).
[CrossRef]

L. Werner, H.-W. Hübers, P. Meindl, R. Müller, H. Richter, and A. Steiger, “Towards traceable radiometry in the terahertz region,” Metrologia 46(4), S160–164 (2009).
[CrossRef]

L. Werner, J. Fischer, U. Johannsen, and J. Hartmann, “Accurate determination of the spectral responsivity of silicon trap detectors between 238 nm and 1015 nm using a laser-based cryogenic radiometer,” Metrologia 37(4), 279–284 (2000).
[CrossRef]

P. Meindl, A. E. Klinkmüller, L. Werner, U. Johannsen, and K. Grützmacher, “New UV spectral responsivity scale of the PTB based on a cryogenic radiometer and an argon plasma arc radiation source,” Metrologia 43(2), S72–S77 (2006).
[CrossRef]

Opt. Express (1)

Other (3)

JCGM, 100:2008 “Evaluation of measurement data — Guide to the expression of uncertainty measurement (GUM)”, http://www.bipm.org/utils/common/documents/jcgm/JCGM_100_2008_E.pdf

PMOD/WRC, http://www.pmodwrc.ch/pmod.php?topic=wrc

A. C. Parr, R. U. Datla and J. L. Gardner, eds., “Optical Radiometry,” Experimental Methods in the Physical Sciences, (Academic Press, San Diego, Ca., 2005) Vol. 41

Supplementary Material (1)

» Media 1: AVI (2804 KB)     

Cited By

OSA participates in CrossRef's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (13)

Fig. 1
Fig. 1

In the case of AC-detection (Fig. 2) the spectral radiance incident on the applied filter combination is given as the difference of the radiances of two blackbodies (red curve) at temperatures of 80 °C and −196 °C calculated according to Planck’s law. As an example the influence of a combination of three long-pass filters (LP – blue curve) on the calculated spectrum is shown. The dominant infrared radiation is sufficiently suppressed. The additional combination with a band-pass filter (BP) yields a selected part of the spectrum around 2 THz, i.e. a center wavelength at 154 µm (green curve).

Fig. 2
Fig. 2

Experimental setup for source-based THz radiometry. The optical beam path is defined by the exit aperture of the blackbody radiator and the entrance aperture of the THz detector.

Fig. 3
Fig. 3

Calculated irradiance at the position of the THz detector for different filter combinations plotted as a function of their center wavelength (blue dots). This wavelength is defined by the condition that the spectrally integrated transmitted powers to its lower and higher wavelength sides are equal. The horizontal bars indicate the bandwidth of the filter combinations which contains 67% of the integrated transmitted power.

Fig. 4
Fig. 4

Irradiance responsivity of two cryogenic silicon-composite bolometers plotted as a function of the center wavelength of the filter combinations of Fig. 3.

Fig. 5
Fig. 5

Irradiance responsivity of the Si-bolometer No. 1 calibrated with different temperatures of the cold reference blackbody while the temperature of the THz blackbody was kept at 80 °C.

Fig. 6
Fig. 6

Irradiance responsivity of a pyroelectric DLATGS detector. The uncertainty bars are the standard deviation of a large signal variation which increases with wavelength due to the decreasing signal to noise ratio (cf. Fig. 3).

Fig. 7
Fig. 7

Experimental setup for the first detector-based THz radiometry.

Fig. 8
Fig. 8

(Media 1) Single-frame excerpts from the video recording of the QCL beam propagation behind a focusing lens at (a) 230 mm and (b) 70 mm in front of the focus. (c) depicts the focus profile and (d) the divergent profile 170 mm behind the focus.

Fig. 9
Fig. 9

Homogeneity of the pyroelectric trap detector measured by horizontal scans at three different heights relative to the laser beam. The reduced half width measured 3 mm above and below the center results from the circular entrance aperture. The insert depicts a schematic sectional drawing of the cavity design with two plane pyroelectric sensor elements behind the aperture.

Fig. 10
Fig. 10

Radial variation of the power responsivity of a silicon-composite bolometer measured by horizontal scans at three different heights relative to the laser beam. The reduced maximum of both scans 2 mm above and below the center reflects the 5% to 8% decreased responsivity of the central scan at ± 2 mm horizontal displacement.

Fig. 11
Fig. 11

Correction factor (compare section 3.2) of the reading of the pyroelectric trap detector for unpolarized THz radiation measured by source- and detector based radiometry. The uncertainty bars are the expanded uncertainty (k = 2, confidence level 95%). In the case of source-based radiometry they reflect only the statistical signal variation, which is insignificant at shorter wavelength but increases strongly with wavelengths due to the decreasing blackbody radiant power at longer wavelengths.

Fig. 12
Fig. 12

Output power of the THz laser at 118 µm as a function of the time after filling with the operating gas CH2F2. Stable output power within +/− 0.4% during a time interval of 30 min is achieved by locking the frequency of the CO2 pump laser to a Fabry-Perot reference. When the stabilization is turned off at time 3:52 h the power drops down immediately (red data points).

Fig. 13
Fig. 13

Specular reflection (incident angle: 12 degree) of a specimen of the absorbing structure of the engineering model for a future primary THz detector standard. The spectra for frequencies between 1 THz and 11 THz are measured at two different mounting positions of the same sample by means of a Fourier transform spectrometer.

Metrics