Abstract
Using ultrafast pump-probe and pump-push-probe spectroscopy we highlight evidence of monodimensional photophysics coming from isolated chains of poly(9,9-dioctylfluorene) (PFO). We identify a large gain band with peak value of 2600 db/cm.
By exploiting the peculiar one-dimensional physics of the isolated chain, we envisage a novel principle for ultrafast all-optical gain switching. Experiments suggest that the expected maximum rate of on-off switching over a broad wavelengths range (around 100 nm) can be as high as 300 GHz with large modulation depth.