Low-cost electrothermally actuated MEMS mirrors for high-speed linear raster scanning

Electrothermally actuated MEMS mirrors are significantly lower in cost than their electrostatically actuated counterparts, largely due to their ability to perform well without hermetic packaging. However, their typical slower speeds, higher power requirement, and non-linear drive limit their widespread use. In this work, we address these limitations and achieve an electrothermally actuated MEMS mirror capable of reliable linear raster scanning at speeds up to 300 Hz with a large angular range of motion (+/- 40 degrees optical). A simple pulse design technique is used to achieve similar to 99% scan linearity and correct for artifacts like overshoot and ringing. Furthermore, segmented polysilicon microheaters along the actuators are used for impedance matching to low-voltage electronics, resulting in lower power consumption and improved scan speed and angular range. These mirrors serve as an attractive option for low-cost and compact integrated beam-steering optical devices, and we demonstrate one such use case in an optical coherence tomography (OCT) system. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement