Dauler, E., Boeuf, N., Mueller, A. J., Datla, R. V., Migdall, A. L., Sergienko, A. V. Measuring Absolute Infrared Spectral Radiance With Correlated Photons: New Arrangements for Improved Uncertainty and Extended IR Range. Metrologia, (1998).

New experimental configurations of a system to measure about IR spectral radiance using correlated photons are presented. The method has the remarkable feature that it allows spectral radiance to be measured in the IR in an intrinsically absolute manner, using only uncalibrated visible detectors. Previous tests of this method have shown the feasibility of the method by demonstrating radiance measurements to nearly 5 micrometers with uncertainties of less than 2%. A new configuration of the previously tested LilO3 down conversion crystal is proposed that allows measurements with better measurement efficiency and uncertainty. A second proposal to measure radiance at 8 micrometers using a new IR crystal is also discussed.