Exceptional gain for the stimulated resonant Raman scattering in the π-conjugated polymer poly(dioctylfluorene)

Stimulated resonant Raman scattering (SRRS) is observed in slab waveguides formed in thin films of the π-conjugated polymer poly(dioctylfluorene) (PFO). The presence of two distinct morphological phases with different electronic bandgaps in these films allows the output frequency of this process to be observed over a much broader range than in other organic materials. In particular, the SRRS peak is pronounced when it is spectrally located in the vicinity of the amplified spontaneous emission bands of the films, which peak at 449 and 463 nm, respectively, for the two different phases, allowing selective tuning in the range of 440-470 nm. Furthermore, the superposition of the SRRS spectral location with that of electronic gain produces an overall gain of 269  cm(-1), making this material extremely attractive for use as an active material in compact Raman lasers.