Two-dimensional distributed feedback lasers using a broadband, red polyfluorene gain medium

We report the fabrication of widely tuneable $(627–702nm)$ optically pumped two-dimensional distributed feedback polymer lasers that utilize a red-emission fluorene copolymer as the active gain medium. The lasers exhibit efficient, low threshold operation and emit highly directional output beams as a result of the enhanced two-dimensional photonic confinement provided by the employed resonator. Their emission and operating characteristics are described in detail. We demonstrate that the very wide spectral range $(Δλ⩾75nm)$ over which these lasers can be systematically tuned is in very good agreement with theoretical predictions based on a simple waveguide model. In addition, we show that the lasers have long operating lifetimes $τ1∕2⩾2×107$ pulses and we discuss the impact that degradation has on the laser output characteristics.