plAn actuation and measurement system of mechanical step displacements with pico-meter resolution using single phase-locked loop, heterodyne interferometry, and piezoelectric driving stage

Abstract

The paper aims to show the possibility of the actuation and the measurement of mechanical step displacements of 10 picometers or less than using a designed piezoelectric (PZT) driving stage and heterodyne interferometry. In our experiment, we use a designed parallel spring stage made by LEX-ZERO (low thermal expansion material) with a high-voltage PZT actuator (0 to -1000 V) to generate mechanical displacements with a step of 10 pm or less than. For a measurement system to achieve these picometer-order displacement measurements, the proposed single phase-locked loop [1] developed on a field-programmable gate array (FPGA) platform aiming to high-resolution phase measurement is used, and a modified heterodyne interferometer with two spatially separated beams is established. Both the actuation and measurement systems are located inside a vacuum chamber for suppressing environmental fluctuations that impact the measurement results. In this paper, the design, instrumentation, and experimental results are discussed. Reference [1] T-D Nguyen, et al., Direct phase determination using phase lock loop for heterodyne displacement-measuring interferometers, Proceedings of Photonic Asia Conference, 2018.