High-precision positioning stage using optical zooming laser interferometer for linear encoder calibration

A high-resolution positioning system for linear encoder calibration was developed. The optical sources were stabilized to a femtosecond optical comb for high accuracy and direct traceability to the optical frequency comb. This system showed a control resolution of 17 pm by using an optical zooming interferometer. The stability of the stage was 4.5 nm at 200 seconds, which can be improved by easy modification of optical setup and lasers.