We report a new calibration setup for laser radiometry at the Physikalisch-Technische Bundesanstalt, the German National Metrology Institute. Measurements of laser diode power of free beam diode lasers in the near infrared spectral range at a wavelength of 808 nm for powers up to 250 W and at wavelengths of 915 nm, 940 nm, and 980 nm for laser powers up to 25 W have been established. The calibration setup, the standard detector, the uncertainty budget and first calibration results will be presented and discussed. The standard uncertainty of the HLR302 standard detector is 0.2%. This uncertainty might be the main contribution to the overall uncertainty in customer calibrations, depending on the quality of the transfer detectors.

We report the results of the first laser high-power measurement comparison between the Physikalisch-Technische Bundesanstalt (PTB, Germany), and the National Institute of Standards and Technology (NIST, USA). Laser power transfer standards were calibrated at both national standards laboratories between 82 W and 127 W at 1.06 µm and between 85 W and 554 W at 10.6 µm. Relative agreement between the standards of the two laboratories was demonstrated to lie between 5 10 -3 and 7 10 -3 , which is well within the combined uncertainties.

A method is described to derive a radiometric scale for laser pulse energies from a scale for CW laser power. The transfer standard used is a commercial glass-disk calorimeter. The sources of measurement uncertainties have been studied and methods for the experimental determination of corrections are described. The achieved relative uncertainty of the scale is about 0,15%.

We report results of the first bilateral laser power comparison for 248 nm KrF excimer lasers accomplished by the National Metrology Institutes of Germany (Physikalisch-Technische Bundesanstalt, PTB) and of the United States of America (National Institute of Standards and Technology, NIST). Laser transfer standards for average power were calibrated at both laboratories. The average powers were approximately 0.5 W, 1 W and 2 W. At 248 nm, the relative agreement was between 1u10 -3 and 6u10 -3 , which is well within the expanded uncertainty of the bilateral degree of equivalence of approximately 2u10 -2 . Thus, this comparison confirms that the measurement procedures of both laboratories are consistent and the uncertainty budgets contain all significant contributions.

In using silicon integrated-circuit technology now, we have developed a new detector for the absolute measurement of radiation fluxes by combining a thin-film thermopile with a (meandered) heating element arranged within the receiving area systen following our former thin-film absolute radiometer conception from 1980 . The sensing junctions and legs of the thermopile and the heater are supported on a thin Si.N4/SiO membrane formed by anisotropic etching of the Si base material. The multijunction thin-film thermopile is fabricated from BiSb and Sb in a muitilayer technique by microlithographic methods. The 76 sensing junctions are arranged on the periphere of the receivi area 7 mm in diyneter. The membrane and chip dimensions are 8 x 8 mm and 12.5 x 12.5 mm , resp. It is intended to minimize both the temperature coefficient (TC) of the responsivity and of the calibration of the device. First measuring results of responsivity of the detector, its TC, linearity, time constant and the local distribution of responsivity are represented and possibilities are shown to improve these parameters by choosing appropriate materials for the heater as well as the thermopile.