Polymer photonic-molecule microlaser fabricated by femtosecond laser direct writing

We report on fabrication of dye-doped polymer photonic-molecule (PM) microlasers by femtosecond laser direct writing (FsLDW) and investigate their lasing behaviors by changing the distance between the two disks in the microcavities. It is found that when the distance of two disks becomes smaller, the coupling between two disks occurs, leading to a decrease of the lasing modes. But, when two disks are crossed, the circular symmetric of whispering-gallery mode cavities are broken, increasing the lasing thresholds. With the three-dimensional (3D) fabrication capacity of FsLDW, our result opens up a possibility of investigating complex 3D coupled microcavities for photonic device integration.