If I deposit silver/gold nanoparticles by EBL or some other techniques on a decladded optical fiber (U-shaped or straight) then when white light is allowed to pass through the optical fiber, will the light coming out of the optical fiber show some absorption in visible domain because of the interaction of the nanoparticles with the light?
Here I am asking about LSPR (Localised Surface Plasmon Resonance) and not SPR (Surface Plasmon Resonance)
Sibasish,
In order to excite LSPR you don't have to satisfy k-vector matching condition as oppose to SPR. Hence, you don't have to have an evanescent wave in your fiber in order to excite the localized plasmon resonance in metal nanoparticles. You can achieve it in much simpler way, for example by depositing Au NPs on a cleaved surface of a fiber. If you measure backreflection in this configuration you would observe a signature of LSPR (say, using MM fiber and a white light source coupled to it).
Serge
In case o NP immobilized U-shaped or straight fiber-optic probe, you will see an absorption through EW and it will be manifested as a dip in transmitted light. For more details, You can refer to the following paper http://www.ncbi.nlm.nih.gov/pubmed/19285853
Yes, you can excite LSPR by evanescent waves. It has been established both theoretically and experimentally. If you don't mind, you may see some of my previous work.
If you are using nanoparticles, any interaction with light will result in plasmon excitation. You could put nanoparticles on the flat endface of the fiber, and the light that transmits through, or reflects backwards, is going to carry the SPR signal of the nanoparticles.
The evanescent wave is important when you need the light to remain confined in the fiber, but still sample the surface. In this case, the transversal orientation is required.
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