Small mass and force metrology at NIST: Redefining the miligram

Recently, the International System of Units (SI) has undergone a massive change. This redefinition frames the SI units of measurement in terms of fundamental physical constants. In the world of mass metrology, this means the primary realization of the kilogram no longer depends on the international prototype kilogram artifact, but is now defined by Planck’s constant. This has some interesting implications for measurement of mass (and force) at scales other than one kilogram. In this talk, I will explain how we scale the unit of mass to a milligram and below using electrostatic forces and in so doing, substantially reduce measurement uncertainty. The application of these new advances allows other new measurements as well, and examples of this will be shown for new laser and radio frequency (RF) power measurement techniques.