The National Institute of Standards and Technology (NIST) has developed a new primary optical watt radiometer (POWR) to accurately measure optical power. This device, designed and built entirely by NIST, provides optical power measurements with an uncertainty of 0.01% (k=1), which has been verified through intercomparisons with other cryogenic radiometer facilities at NIST.
POWR is located next to NIST’s Spectral Irradiance and Radiance using Uniform Sources (SIRCUS) facility, allowing access to a variety of lasers for scale transfer to portable detectors. This enables high-accuracy measurements across different wavelengths and power levels, which is crucial for understanding and monitoring solar irradiance.
The modularity of the critical detector section in POWR allows for the design and construction of new detector modules that can be optimized for specific transfer wavelengths and power levels. This flexibility enables NIST to adapt the POWR to emerging technologies and changing measurement needs, with significant implications for climate modeling, renewable energy, and other applications that rely on accurate solar irradiance measurements.
Source: https://www.nist.gov/programs-projects/primary-optical-watt-radiometer-powr
Keywords: metrology, optical power, uncertainties
