Visibility of plasmonic particles embedded in transparent materials

Recently, several experiments have shown that it is possible to visualize the optical near-field generated around individual plasmonic particles through the photo-induced structuration of polymer films. In this communication, we show that the particle visibility can be controlled at will down to the quasi-invisibility by tuning the incident wavelength around the plasmon frequency. This phenomenon occurs when the real part of the particle polarizability displays a sign change. This simple spectrally controlled visibility is an alternative to the more classical spatially controlled visibility approach.