Breakthrough in Signal Enhancement
Now, in a study published on October 28 in the journal Light: Science & Applications, scientists from Osaka University described a new method for the long-range enhancement of fluorescence and Raman signals using a dense random array of Ag nanoislands.
The analyte molecules are kept separate from metal structures using a 100-nm thick column-structured silica layer. This layer is thick enough to protect the molecules being studied, but at the same time thin enough for the collective electromagnetic oscillations in the metal layer, called plasmons, to enhance the spectroscopic signal.
“We demonstrated that the range of influence of plasmons in metals can exceed 100 nanometers, far beyond what conventional theory predicted,” lead author Takeo Minamikawa says.