High-Q conical polymeric microcavities

Abstract

We report on the fabrication of high-Q microresonators made of low-loss, thermoplastic polymer poly(methyl methacrylate) (PMMA) directly processed on a silicon substrate. Using this polymer-on-silicon material in combination with a thermal reflow step enables cavities of conical geometry with an ultrasmooth surface. The cavity Q factor of these PMMA resonators is above 2×106 in the 1300 nm wavelength range. Finite element simulations show the existence of a variety of “whispering gallery” modes in these resonators explaining the complexity of the measured transmission spectra.