Unidirectional Lasing From a Spiral-Shaped Microcavity of Dye-Doped Polymers

We experimentally demonstrate fabrication of a spiral-shaped polymer microdisk cavity by femtosecond laser direct writing via two-photon polymerization of dye-doped resins. This spiral microresonator supports highly directional emission from the notch with a high-Q factor exceeding 1.6 × 10³ and a low lasing threshold at room temperature. Our numerical simulation results reveal that clockwise propagating high-Q whispering gallery-like modes may couple to the counterclockwise modes and give the directional output. Benefiting from the low cost and good chemical compatibility of polymer materials, the fabrication of such spiral-shaped polymer microlasers with high-Q and unidirectional emission holds great potentials for use as elements of integrated organic optoelectronic devices.