Two wavelength band emission WGM lasers via photo-isomerization

Abstract Wavelength switchable microcavity is indispensable component for various integrated photonic devices. However, achieving two wavelength band emission of the whispering gallery mode (WGM) laser is challenging. Here, we propose a strategy to realize two wavelength band emission WGM lasers activated by photo-isomerization based on excited-state intramolecular proton transfer (ESIPT) process in isolated/coupled polymer microfiber cavities. The WGM microcavity is built by highly polarized organic intramolecular charge-transfer (ICT) dye molecules. The two cooperative gain states of ICT dye molecules can be controlled by optimizing energy levels. Thereby, the lasing wavelength can be reversibly switched under photo-isomerization activated in the ESIPT energy-level progress. The photonic bar code can be generated by following the strategy of proposed design. This work provides a promising route to achieve switchable WGM laser in on-chip photonic integration.