Multimode laser emission from dye-doped hollow polymer optical fibre

Well-resolved multimode laser emission was observed for the first time from a freestanding microring cavity based on Rhodamine B dye-doped hollow polymer optical fibre by transverse pumping. Fibres with different diameters such as 180, 460, 640 and 800 μ m were fabricated from a dye-doped hollow polymer preform. A blueshift in the mode structure was observed with decrease in fibre diameter leading to wide range tunability of the laser emission.