Kerr versus thermal non-linear effects studied by hybrid whispering gallery mode resonators

Whispering-gallery-modes (WGM) spherical microresonators may reveal new perspective properties being coated with non-linear thin layers. We present the examples of all-optical switching of WGM in silica microspheres covered with a polyfluorene derivative showing ultrafast Kerr nonlinearity, or a relatively slow thermal nonlinearity. Another set of measurements performed with an inert polymer, an acrylate derivative, is discussed as well