The article discusses NIST’s efforts to maintain and develop methods for traceability to the meter using laser frequency/wavelength measurements. The main focus is on improving the accuracy of length measurements by developing accurate refractometers to reduce uncertainty in air’s index of refraction.
Key developments include:
1. A 2017 paper describing a sub-15 ppm realization of the pascal using optical interferometry with the MIRE apparatus
2. Rebooting Parks and Faller’s big-G apparatus to measure pendulum bob displacement using Fabry Perot interferometry
3. Achieving +/- 50 pm stability over 10 hours with the MIRE apparatus, making it one of the world’s most stable Michelson interferometers
Technical goals include:
– Post-doctoral opportunity in dimensioning
– Subpicometer displacement interferometry and submicrometer mechanical metrology for Newton’s constant
– Engaging NIST Sensor Science Division stakeholders
Source: https://www.nist.gov/programs-projects/si-length-and-traceability
Keywords: Metrology, Interferometry, Refractometers, Wavelength, Displacement
