Tuning the wavelength of amplified spontaneous emission coupled to localized surface plasmon

Amplified spontaneous emissions (ASEs) with a tuned wavelength have been observed in a thin film composite made by spin-coating a dye-doped polymer layer (thickness similar to 80 nm) on Ag nanoparticles deposited on a SiO2 substrate. The samples having a varied wavelength of the localized surface plasmon resonance (LSPR) are excited with second harmonic pulses from a Nd3+ doped yttrium aluminum garnet laser. When the pump energy exceeds a threshold, a spectrally narrow peak appears on a broad emission from dye molecules with a nonlinear increase in emission intensity, indicating an onset of ASE. It is found that the peak wavelength of ASE shifts with the change of the wavelength of LSPR. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4736408]