A portable picometer reference actuator with 100 μm range, picometer resolution, subnanometer accuracy and submicroradian tip-tilt error for the characterization of measuring instruments at the nanoscale

We present the realization and the characterization of a picometer reference actuator (PRA), a metrological instrument based on a precision linear actuator capable of 100 mu m range with subnanometer accuracy, picometer resolution, and submicroradian tip-tilt pointing control. The PRA relies on an integrated multiple reflections homodyne interferometer as a high resolution and accurate internal reference, on a multiple reflection based angle sensor for the control of the movement straightness, and on a versatile mirrors configuration to transfer the metrological traceability to an external device. As an example case we report the use of the PRA for the characterization of the non-linearities of the INRIM heterodyne interferometer dedicated to the calibration of capacitive sensors.