Nanoengineering of optical resonances

Metal nanoshells, consisting of a dielectric core with a metallic shell of nanometer thickness, are a new, composite nanoparticle whose optical resonance can be “designed in” in a controlled manner. By varying the relative dimensions of the core and shell, the optical resonance of these nanoparticles can be varied over hundreds of nanometers in wavelength, across the visible and into the infrared region of the spectrum. We report a general approach to the making of metal nanoshell composite nanoparticles based on molecular self-assembly and colloid reduction chemistry.