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Recent research and development in photometry at NIST



Yuqin Zong, Maria Nadal, Benjamin K. Tsai, C Cameron Miller


Many developments were made in recent years in photometry at NIST for reducing measurement uncertainties, increasing calibration efficiencies, and adding measurement capabilities. The 40 years old photometry laboratory has been renovated. The new laboratory is equipped with an automated 5 m photometry bench, which has a 1.5 m travel translation stage for carrying various light sources and a 0.8 m travel translation stage for mounting photometers and other optical sensors. All light sources and photometers are aligned and ready for use. The light source or photometer is switched from one to another automatically depending on the calibration need. The distance uncertainty of the new photometry bench is 50 μm, which is achieved using an absolute linear encoder and a new microscope-based alignment technique. A new set of photometers are developed and used for realization of the NIST luminous intensity scale. The uncertainty of the luminous intensity scale is improved significantly by calibrating the new photometers directly against reference trap detectors for spectral irradiance responsivities using tunable lasers. This laser-based calibration facility is also used for calibrating spectroradiometers to achieve a calibration uncertainty that is expected to be much smaller compared to that using a conventional standard lamp based calibrated system.
Proceedings Title
CORM 2019 Annual Technical Conference and 12th Biennial Joint Meeting of the CNC/CIE and
Conference Dates
October 28-31, 2019
Conference Location


Calibration, Optical bench, Photometer, Photometry, Spectroradiometer


Zong, Y. , Nadal, M. , Tsai, B. and Miller, C. (2021), Recent research and development in photometry at NIST, CORM 2019 Annual Technical Conference and 12th Biennial Joint Meeting of the CNC/CIE and CIE-USNC, Ottawa, , [online], (Accessed May 19, 2024)


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Created April 22, 2021