Nanolocalised source of femtosecond radiation

Possible spatial localisation of femtosecond laser radiation to the size on the order of 50 nm is studied. An approach to femtosecond laser radiation localisation in the nanometre scale is based on the use of nonlinear processes in metal nanostructures. It is shown that the extremely high third-order optical susceptibility of metal nanostructures and strong plasmon resonances give a possibility to realise an efficient nanolocalised source of radiation at the third harmonic frequency and a wideband femtosecond radiation based on metal photoluminescence.