This report presents the discovery of greatly enhanced, broad-range, multiphoton excited emission from Ag aggregate-adsorbate complexes seeded into a cylindrical microcavity. The emission spectrum contains descrete peaks spanning the wavelength range from the 632 nm HeNe laser exciting wavelength down to 200 nm. Observation of multiphoton processes at the low exciting light intensity (20 W/cm2) became possible due to using a fractal-microcavity composite, where coupling the localized plasmon modes in fractal aggregates with microcavity resonances is provided. The important role of the multiphoton resonant transitions between discrete states of a finite-size metal particle in enhanced local fields is shown. Analysis, based on the model of a spherical potential well, shows that the observed spectra contain fingerprints of the quantum size effect.
|Number of pages||10|
|Journal||Proceedings of SPIE - The International Society for Optical Engineering|
|Publication status||Published - 2002|