Characterization of Rotational Mode Disk Resonator Quality Factors in Liquid

This work presents several variations of microscale single and multiple coupled thermally actuated rotational mode disk resonators capable of high quality factor (Q) operation in liquid. All surfaces of a rotational mode disk resonator slide in parallel to the liquid interface (rather than stroking against it). This minimizes interactions with the surrounding fluid and therefore viscous damping. Quality factors as high as 304 have been demonstrated for rotational mode disk resonators in liquid, which is more than 3X higher than the highest values previously demonstrated for other types of microscale resonators. Based on the measurement results it is suggested that most of the energy loss into the surrounding liquid is through the sidewalls of the disks. This could be blamed on the sidewall roughness caused by deep reactive ion etching, off-center rotation of the disks due to fabrication induced asymmetries, and slight bending of support beams during resonance. Much higher Q values are expected to be achievable by minimizing such limiting factors.