Nanometer Positional Control using Magnetic Suspension for Vacuum-to-Air Mass Metrology.

5 20 × 10

Progress on vacuum-to-air mass calibration system using magnetic suspension to disseminate the Planck-constant realized kilogram.

The kilogram is the unit of mass in the International System of units (SI) and has been defined as the mass of the International Prototype Kilogram (IPK) since 1889. In the future, a new definition of the kilogram will be realized by fixing the value of the Planck constant. The new definition of the unit of mass will occur in a vacuum environment by necessity, so the National Institute of Standards and Technology (NIST) is developing a mass calibration system in which a kilogram artefact in air can be directly compared with a kilogram realized in a vacuum environment.

Cavity-enhanced measurements for determining dielectric-membrane thickness and complex index of refraction.

The material properties of silicon nitride (SiN) play an important role in the performance of SiN membranes used in optomechanical applications. An optimum design of a subwavelength high-contrast grating requires accurate knowledge of the membrane thickness and index of refraction, and its performance is ultimately limited by material absorption. Here we describe a cavity-enhanced method to measure the thickness and complex index of refraction of dielectric membranes with small, but nonzero, absorption coefficients.

Dynamic and static measurement of interfacial capillary forces by a hybrid nanomechanical system.

The forces resulting from the presence of interfacial liquids have mechanical importance under ambient conditions. For holistic understanding of the liquid-mediated interactions, we combine the force-gradient sensitivity of an atomic force microscope (AFM) with the force measuring capability of a micro-electromechanical force sensor. Simultaneous measurement of the viscoelasticity of the water nanomeniscus and the absolute capillary force shows excellent agreement in its entire length, which justifies the validity of the widely used AFM results.

Low-volume liquid delivery and nanolithography using a nanopipette combined with a quartz tuning fork-atomic force microscope.

Electric-field-induced low-volume liquid ejection under ambient conditions was realized at a low bias potential of 12 V via a nanopipette (aperture diameter of 30 nm) combined with a non-contact, distance-regulated (within 10 nm) quartz tuning fork-atomic force microscope. A capillary-condensed water meniscus, spontaneously formed in the tip-substrate nanogap, reduces the ejection barrier by four orders of magnitude, facilitating nanoliquid ejection and subsequent liquid transport/dispersion onto the substrate without contact damage from the pipette. A study of nanofluidics through a free-standing liquid nanochannel and nanolithography was performed with this technique.