National Institute of Standards and Technology high-accuracy cryogenic radiometer

Area of Science:

• Metrology
• Optical Physics
• Cryogenics

Background:

• Accurate optical power measurement is crucial for scientific and technological applications.
• Existing standards face limitations in precision and scope.
• The National Institute of Standards and Technology (NIST) addresses this need.

Purpose of the Study:

• To develop and characterize a high-accuracy cryogenic radiometer.
• To establish a primary standard for optical power measurements.
• To quantify measurement uncertainties at cryogenic temperatures.

Main Methods:

• Design and construction of an electrical-substitution radiometer.
• Operation of the radiometer at cryogenic temperatures.
• Detailed analysis of optical power measurement uncertainties.

Main Results:

• Achieved a relative standard uncertainty of 0.021% at 0.8 mW optical power.
• Demonstrated the radiometer's capability as a primary standard.
• Provided comprehensive data on measurement uncertainties.

Conclusions:

• The developed cryogenic radiometer serves as a reliable primary standard for optical power.
• Cryogenic operation significantly enhances measurement accuracy.
• This advancement supports improved precision in optical metrology.