Nanopatterning on rough surfaces using optically trapped microspheres

While nanofabricated structures find an increasingly large number of applications, few techniques are able to pattern rough or uneven surfaces, or surfaces with pre-existing structure. In this letter we show that optical trap assisted nanopatterning (OTAN), a near-field laser based technique, is able to produce nanoscale features on surfaces with large roughness but without the need for focus adjustment. Patterning on model surfaces of polyimide with vertical steps greater than 0.5 mu m shows a high degree of uniformity, demonstrating that OTAN is a suitable technique to pattern nontraditional surfaces for emerging technologies. (C) 2011 American Institute of Physics. [doi:10.1063/1.3598427]