Nonlinear formation of photonic microresonators by slow optical cooking

Recently we discovered the slow cooking phenomenon which uses a broadband light source exciting whispering gallery modes (WGMs) at a water-filled silica microcapillary fibre (MCF) to create photonic microresonators [1] . This method exploits the very slow interaction of silica and WGM-heated water leading to permanent changes of the silica material. It significantly expands the approaches developed previously for fabrication of permanent and transient miniature resonant devices at the optical fibre surface (see, e.g. [2] , [3] ).