We investigated the amplified spontaneous emission (ASE) properties of the β-phase of poly(9,9-dioctylfluorene) at T = 5 K. We observe ASE at about 478 nm with a threshold as low as 50 μJ cm−2. For excitation density higher than 350 μJ cm−2 a clear spectral rebroadening and a progressive ASE intensity saturation, ascribed to gain saturation, are observed. The gain saturation at 478 nm leads to ASE from the 470 nm vibronic band, with a threshold of about 3.0 mJ cm−2. We show that these effects are due to the break down, at high excitation density, of the four level amplifier scheme, typically applied to conjugated polymer films.
Spectral effects of gain saturation in the β-phase of Poly(9,9-dioctylfluorene)
ANNI, Marco;
2008-01-01
Abstract
We investigated the amplified spontaneous emission (ASE) properties of the β-phase of poly(9,9-dioctylfluorene) at T = 5 K. We observe ASE at about 478 nm with a threshold as low as 50 μJ cm−2. For excitation density higher than 350 μJ cm−2 a clear spectral rebroadening and a progressive ASE intensity saturation, ascribed to gain saturation, are observed. The gain saturation at 478 nm leads to ASE from the 470 nm vibronic band, with a threshold of about 3.0 mJ cm−2. We show that these effects are due to the break down, at high excitation density, of the four level amplifier scheme, typically applied to conjugated polymer films.File in questo prodotto:
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