We have used transmission electron microscopy and scanning electron microscopy to study the microstructure in polycrystalline 200 nm thick copper thin films that are geometrically confined between transparent amorphous silicon oxide layers after single pulse laser melting and rapid lateral solidification (RLS). The microstructure consisted predominantly of directionally solidified grains with an in-plane columnar structure and dimensions of up to 22 pin long and about 1 pm wide. A < 100 > preferred orientation in the vicinity of the average growth direction in the thin film plane has been identified for these high aspect ratio columnar grains produced by RLS in this Cu thin film12. (C) 2008 Elsevier B.V. All rights reserved.