Light Controlled Assembly of Silver Nanoparticles

Strong interaction of light with free electrons in metals makes it possible to localize and manipulate electromagnetic waves far beyond sub-wavelength dimensions. Enhanced absorption and scattering properties of metal... [ view full abstract ]

Strong interaction of light with free electrons in metals makes it possible to localize and manipulate electromagnetic waves far beyond sub-wavelength dimensions. Enhanced absorption and scattering properties of metal nanoparticles enable light controlled growth and alignment with nanometer accuracy positioning. Here, we show the light controlled alignment of silver nanoparticles from liquid phase on a plane glass substrate with an estimated accuracy of well below 20 nm. During that alignment process, nanoparticles growth occurs in the position of maximum local intensity. In this way, an interdependency of light influencing the nanostructure and the nanostructure influencing the light is observed, leaving a unique fingerprint of used wavelength, polarisation and incident angle of the incoming electromagnetic wave on the grown nanostructure. Moreover, by introducing a light confining structure we were able to pattern the silver nanoparticles at the areas of local maximum intensity of counter-propagating dielectric modes excited at a nano gap in a metal stripe. The experimentally and theoretically proven approach combines the accurate positioning of top-down approaches with the benefits of bottom-up fabrication with an emphasis on facile processing under vacuum free conditions.