Near field photothermal printing of gold microstructures and nanostructures

We report on a rapid near field photothermal printing (NPTP) approach for fabricating gold microstructures and nanostructures guided by flexible and transparent polymer molds. The optical energy of nanosecond laser pulse is spatially redistributed by a PDMS phase-shifting mask, resulting in selective gold melting in light intensity enhanced areas. The melted gold migrates to cold areas and forms desired structures after cooled down. Using NPTP, we have demonstrated rapid laser printing of periodic gold nanowire array with a 320 nm linewidth, nanosphere arrays with 400 nm in diameter, and nonperiodic structures across a 1 mm2 area with few laser pulses.