Variable-temperature device for precision Casimir-force-gradient measurement

摘要

We present the design and use of an instrument that is based on a microcantilever to perform precision force gradient measurements. We demonstrate its performance through measurements of the Casimir pressure at various temperatures. The instrument can operate in high vacuum environments and temperatures between 5 K and 300 K. It uses an all-fiber optical interferometer to detect the resonant-frequency shift of a customized microcantilever due to the presence of a force gradient. To measure this shift we use both, a technique of frequency-modulation atomic force microscopy and the direct recording of the thermomechanical resonant frequency.