Field amplification in Na clusters

Abstract:

We study the amplification of an incoming fs laser pulse through the resonant plasmon response in a metal cluster taking Na clusters as test case and using density-functional theory for the description of the electronic dynamics. We find large amplification factors for moderate laser intensities. The effect shrinks for higher intensities because the binding forces of the electron cloud set a limit for the effective fields. The response shows resonant behaviour much similar to an harmonic oscillator. It is found to be independent of cluster size.