Photonic Micro-Electromechanical Systems Vibrating at X-band (11-GHz) Rates

We report on an opto-mechanical resonator with vibration excited by compressive radiation pressure via stimulated Brillouin scattering [SBS]. We experimentally excite a mechanical whispering-gallery mode (WGM) from an optical WGM and detect vibration via the red Doppler shifted (Stokes) light it scatters. We numerically solve the stress-strain equation to calculate the circumferentially circulating mechanical WGM and reveal mechanical WGMs with a variety of transverse shapes. Frequency in our device is limited by the shortest optical wavelength it can transmit, irrespective of device size.