Comb-referenced metrology laser for interferometric length measurements in nanopositioning and nanomeasuring machines

In this article a new approach for the direct traceability of interferometric length measurements in nanopositioning- and measuring machines is presented. The concept is based on an optical frequency comb tied to a GPS disciplined oscillator. The frequency comb serves as a highly stable reference laser with traceable optical frequencies. By directly stabilizing the metrology lasers of a nanopositioning and -measuring machine to a single comb line a permanent link of the laser frequency to an atomic clock is created allowing direct traceability to the SI meter definition. The experimental conditions to provide traceability will be discussed. Furthermore, it is demonstrated how the long-term frequency stability of an individual comb line can be transferred onto the metrology lasers enhancing their stability by three orders of magnitude.