This article shows how a direct readout of the interferometric length measurement in nanopositioning machines can be transferred by connecting the metrology laser to a frequency comb line. The approach is based on a GPS-referenced frequency comb with which the stability of the timer (atomic clock via GPS) is transferred to the metrology laser of the nanopositioning and nanomeasuring machine NPMM-200. The necessary prerequisites for ensuring traceability are discussed. It is demonstrated that with this approach an improvement in the long-term stability of the metrology laser by three orders of magnitude can be achieved.
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