Symmetric nanostructuring and plasmonic excitation of gold nanostructures by femtosecond Laguerre–Gaussian laser beams

Femtosecond low-energy Laguerre–Gaussian pulses of tightly focused visible laser radiation were employed for singlepulse ablative nanostructuring of a 50-nm thick gold film. Similar pulses of lower energy were employed for the efficient plasmonic photoluminescence excitation of a rhodamine 6G dye monolayer in the fabricated nanostructures. The consistency between the shape and polarisation symmetries of the low-energy laser beam, on the one hand, and the gold nanostructures produced by the same beam at a high radiation energy, on the other hand, opens the way to consistent nanostructuring and surface-enhanced analytical spectroscopy with the use of nanostructures.