Metallic nanostructures have been prepared by depositing thin layers of gold onto a fused-silica transmission grating. Excitation with 800-nm femtosecond laser pulses in air results in the emission of terahertz radiation with an angle-dependent efficiency and a third-order dependence on input power. Nanostructures consisting of metal nano-pyramids on glass as well as silver nano-pyramid arrays covered in gold also exhibit terahertz emission. We will show that the source of the terahertz radiation in all of these cases is surface-plasmon-assisted multiphoton ionisation and ponderomotive acceleration in the evanescent laser field.
|Title of host publication||2007 Joint 32nd International Conference on Infrared and Millemeter Waves and 15th International Conference on Terahertz Electronics|
|Place of Publication||New York|
|Number of pages||1|
|Volume||Vols 1 and 2|
|Publication status||Published - 3 Sep 2007|
- terahertz pulse generation
- surface waves
- electron emission
Welsh, G. H., Hunt, N. T., & Wynne, K. (2007). Terahertz-pulse emission by laser excitation of surface plasmons in a metal grating. In 2007 Joint 32nd International Conference on Infrared and Millemeter Waves and 15th International Conference on Terahertz Electronics (Vol. Vols 1 and 2, pp. 884-885). IEEE.