Paper MN-TuM6
Heterodyne Optical Detection of Mechanical Resonances of Ultra High Frequency Silicon Micro-Resonators

Tuesday, October 21, 2008, 9:40 am, Room 206

Recent advancement in microscale electromechanical systems fabrication and operation demonstrated ultra high mass and force sensitivity. Here we investigate the parameters affecting the ultimate sensitivity of suspended mechanical resonators, in particular the resonance frequency and quality factor scaling as the resonators dimensions are reduced. The silicon resonators are fabricated by e-beam lithography with length ranging from 20 um down to 500 nm and having a width of 500 nm. The suspended resonators are actuated using electrostatic force acting between the suspended beam and side gates and an optical heterodyne interferometry is used to detect the resonant oscillations. The heterodyne interferometry has a large bandwidth allowing resonance frequency detection above Ghz and has a detection sensitivity of 10 pm. For fundamental oscillation modes up to 220 MHz, the quality factor of resonance were over 20000 in high vacuum at room temperature and increased in the explored range. We present experimental approaches to detect both flexural and transversal oscillation modes for silicon micro-resonators using our optical detection scheme.