Lasing Action in Dye Doped Polymer Nanofiber Knot Resonator

Here we demonstrated laser emission from a dye doped polymer nanofiber knot ring resonator. Dye doped polymer nanofiber was fabricated by flame assisted general fiber drawing technique. After bending the fiber to a knot ring resonator, lasing action with 0.07-nm linewidth was observed. From the relation between mode spacing and diameter of ring cavity, the lasing action was considered to be formed by whispering gallery modes.