Fluorene-based polymer gain media for solid-state laser emission across the full visible spectrum

We report a study of the optical gain properties of three polyfluorenes with chemically tuned emission characteristics that span 400–800 nm. We demonstrate low threshold light amplification in the blue, green, and red spectral ranges via amplified spontaneous emission (ASE) in optically pumped planar asymmetric waveguides. Gain and loss measurements at the peak ASE wavelengths show large net gains, $\text{22⩽g⩽66\hspace{0.5em}}{\mathrm{cm}}^{\text{−1}},$ and low losses, 15⩾α⩾3 ${\mathrm{cm}}^{\text{−1}}.$ Our findings establish fluorene-based polymers as an attractive family of materials for use in tuneable solid-state lasers that emit at wavelengths across the whole visible spectrum.