Plasmonic nano-printing: large-area nanoscale energy deposition for efficient surface texturing

Abstract

The lossy nature of plasmonic wave due to absorption is shown to become an advantage for scaling-up a large area surface nanotexturing of transparent dielectrics and semiconductors by a self-organized sub-wavelength energy deposition leading to an ablation pattern—ripples—using this plasmonic nano-printing. Irreversible nanoscale modifications are delivered by surface plasmon polariton (SPP) using: (i) fast scan and (ii) cylindrical focusing of femtosecond laser pulses for a high patterning throughput. The mechanism of ripple formation on ZnS dielectric is experimentally proven to occur via surface wave at the substrate–plasma interface. The line focusing increase the ordering quality of ripples and facilitates fabrication over wafer-sized areas within a practical time span. Nanoprinting using SPP is expected to open new applications in photo-catalysis, tribology, and solar light harvesting via localized energy deposition rather scattering used in photonic and sensing applications based on re-scattering of SPP modes into far-field modes. Femtosecond laser pulses focused onto a dielectric induce ripples on its surface that are useful for photovoltaic and sensing applications. Light-driven excitation of surface charge waves—plasmons—achieves light localization on surfaces down to the deep-subwavelength nanoscale. Now, Hong-Bo Sun of Jilin University in China and co-workers from China and Australia have used surface plasmon polaritons to create permanent surface modifications whose period is smaller than the laser wavelength. They achieved this by using a cylindrical lens to create a line focus for near-infrared ultrashort laser pulses on silicon and zinc sulfide surfaces. This nanoprinting technique is well suited for texturing large areas on a wafer scale, since the patterning speed is determined simply by the repetition rate of the laser used. Potential applications include enhanced light harvesting for solar cells and improved photocatalysis.