Scatterer induced mode splitting in poly(dimethylsiloxane) coated microresonators

We investigate scatterer induced mode splitting in a composite microtoroidal resonator $(Q∼106)$ fabricated by coating a silica microtoroid $(Q∼107)$ with a thin poly(dimethylsiloxane) layer. We show that the two split modes in both coated and uncoated silica microtoroids respond in the same way to the changes in the environmental temperature. This provides a self-referencing scheme which is robust to temperature perturbations. Together with the versatile functionalities of polymer materials, mode splitting in polymer and polymer coated microresonators offers an attractive sensing platform that is robust to thermal noise.