Interferometric sensor and calibration system for high-precision applications

This paper describes the basic principle of an interferometric angle and length sensor and its application. The sensor is the main part of a compact calibration system that can be used to calibrate and test one-dimensional length measurement systems. It is built by integrating the sensor into a positioning stage and setting up a DSP-based hardware and software signal processing system. A PC-based frontend using Matlab allows for easy setup of user-specific scripts for numerous calibration tasks. The sensor's and system's capabilities have been demonstrated using a high-resolution autocollimator, an AFM and an inductive tactile probe as calibration samples. Calibrations are possible with step sizes ranging from 20pm up to ±6μm and several waveforms for dynamic calibrations at frequencies currently up to 2 kHz.