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

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Abstract
We report the fabrication of widely tuneable ( 627 – 702 nm ) 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 ( Δ λ ⩾ 75 nm ) 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 τ 1 ∕ 2 ⩾ 2 × 10 7 pulses and we discuss the impact that degradation has on the laser output characteristics.