Optical tweezers with enhanced efficiency based on laser-structured   substrates
  We present an optical nanotrapping setup that exhibits enhanced efficiency, based on localized plasmonic fields around sharp metallic features. The substrates consist of laser-structured silicon wafers with quasi-ordered microspikes on the surface, coated with a thin silver layer. The resulting optical traps show orders of magnitude enhancement of the trapping force and the effective quality factor. 
D. G. Kotsifaki, M. Kandyla, I. Zergioti, M. Makropoulou, E.   Chatzitheodoridis, A. A. Serafetinides
cond-mat.mtrl-sci physics.optics