Abstract
This paper reports the first torsional micro-actuator using a lithium niobate (LiNbO 3 , 36° Y-cut) thin film with a record-high figure of merit (mathrm{FoM}= heta-{opt}cdot ext{mirror dimension}cdot mathrm{frequency}) of 1582 °·mm·kHz at a resonance frequency of 1.268 MHz. The large piezoelectric coefficients and high-quality factors of single crystal LiNbO 3 have been exploited to enable high coupling torsional actuation. The fabricated actuator has a mirror size of 22mathrm{x}40 mu mathrm{m} {2}, and quality factors of 547 and 1497 in air and vacuum respectively. Moreover, the optical angle can exceed 31 {circ} ( heta-{opt}= 4cdot heta-{mech}) in both air and vacuum, leading to an FoM surpassing state-of-the-art high-frequency scanners. Our demonstration has shown great potential for scanning micro-mirrors, and light detection and ranging systems (LIDAR) applications where frequency scalability, scanning angles, and footprint are the main challenges.