Operating characteristics of a traveling-wave semiconducting polymer optical amplifier

Abstract
We report a study of light amplification in dilute solutions of the semiconducting polymer poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT). The operating characteristics of the F8BT solutionamplifier are investigated in detail, and we show that it provides a large optical gain ( > 40 dB ∕ cm ) across a wide ( > 48 nm ) spectral bandwidth in the green. The saturation characteristics of the amplifier are found to be in excellent agreement with theoretical predictions, allowing an estimate of the F8BT stimulated emission cross-section, σ . We find σ ∼ 1.7 × 10 − 16 cm 2 , comparable with the reported values for established laser dyes and other high-gain conjugated polymers.