Laser transfer of silicon nanoparticles with optical magnetic response

Controlled generation of spherical nanoparticles with a reproducible size and their precise positioning on a specific location on a sample is still a challenging problem. We have developed a novel laser printing technique for the controlled fabrication and precise deposition of spherical silicon nanoparticles. Using femtosecond laser pulses it is possible to vary the size of Si nanoparticles and their crystallographic phase. The generated silicon nanoparticles with sizes of a few hundred nanometres exhibit unique optical properties due to their strong electric and magnetic dipole responses in the visible range. The novel fabrication technology allows the generation of individual amorphous and crystalline spherical Si nanoparticles with precisely controlled optical properties. The laser-printed nanoparticles are initially in amorphous phase (a-Si). By additional single-pulse laser irradiation, the amorphous nanoparticles can be controllably transformed into crystalline particles (c-Si) or into particles with more complex mixed amorphous/crystalline phases. This technology provides unique possibilities for laser tuning of optical properties of individual Si nanoparticles.