Suppressing mechanical dissipation of diamagnetically levitated oscillator via engineering conductive geometry

Diamagnetically levitated oscillators of millimeter and submillimeter size are emerging ultrasensitive sensors for gravitylike force and acceleration measurements. However, improving the levitation capability while keeping mechanical dissipation low remains an open challenge. Here, we propose and experimentally demonstrate an engineering conductive geometry scheme to efficiently reduce the mechanical dissipation of a diamagnetically levitated oscillator made of pyrolytic graphite. We show that with a specially designed conductive geometry, the eddy current damping is reduced, and the reduction factor increases as the engraving pattern being denser. Under high vacuum and room temperature, eddy current damping is the dominant contribution to mechanical dissipation, and we reduce it by a factor of 50 in the experiment. Our work opens up a new way to achieve diamagnetically levitated oscillator with ultralow mechanical dissipation and strong levitation capability, a candidate platform for studying a broad range of fundamental physics.