Abstract

Silica microspheres possess ultra-high-Q optical whispering gallery modes (WGMs), while simultaneously exhibiting mechanical modes in the radio frequency range that can be excited by radiation pressure force. When entering the regime where the photon lifetime is comparable to the mechanical oscillation period and the cavity is pumped with a laser whose frequency slightly exceeds the WGM resonance (i.e. blue-detuned excitation), this mutual coupling gives rise to a parametric oscillation instability which is characterized by regenerative mechanical oscillation of the mechanical eigenmodes¹. In contrast to earlier studies of vibrational modes of nanospheres using Raman or Brillouin scattering from ensembles, we report here the parametric oscillation instability in single microspheres in a larger diameter range (35-1 10μm in our case).

© 2007 IEEE