Phase-shifting interferometry: A method for generating phase shifting by pressure variation

The phase-shifting device consisted of a monolithic quartz component is designed and optimized by simulative calculation based on a mathematic model. With a safety and stability consideration, the phase-shifting device can produce at least 2 μm phase-shifting in two-channel. And the phase-shifting can be continuously measured using precision capacitor sensor with an uncertainty of 0.05 nm. This paper provides a novel technique to measure the dimension of an object, especially to determine the diameter of a silicon sphere for Avogadro constant project.