Thursday, 15 March, 2012

Designer lights from the physics lab

Precise tailoring of light beams with DNA origami

Nowadays cups of yoghurt have a note telling you that the product contains L(+)-lactic acid, one of two forms that differ in the spatial arrangement of their atoms. The twoisomers, L(+) and D(-), have different optical activities, turning the plane of polarized light to the right or left respectively. Of course the capacity to alter the polarization, intensity or color of light is not confined to solutions of yoghurt. Light interacts in one way or another with all matter. Now an international team led by CeNS member Tim Liedl has fabricated a new type of optically active, three-dimensional structures which allow one to tailor the properties of visible light in virtually any desired fashion. Their method is based on DNA origami: DNA strands that fold spontaneously into precise shapes (determined by their nucleotide sequence) serve as scaffolds for the attachment of gold nanoparticles in predetermined patterns. In their experiments the researchers chose left- and right-handed helical arrangements for the gold particles. By the appropriate choice of parameters, the team was able to tune the interaction of light with the metal particles. This new approach opens up the route to the preparation of self-assembling metamaterials and eventually to the construction of novel types of lenses. (Nature online, 14 March 2012)

Press information LMU (english)
Presseinformation der LMU (deutsch)
Publication "DNA-based self-assembly of chiral plasmonic nanostructures with tailored optical response"