Functional nanoparticles are powerful tools in applied nanotechnology. In particular, noble metal nanoparticles and iron oxide nanoparticles attracted a great interest for their properties related, respectively, to surface plasmon resonance and to magnetism. Moreover, the control of surface chemistry and functionalization/bioconjugation are indispensable steps for real applications. Laser ablation synthesis in solution (LASiS) is an easy, versatile and rapid technique for obtaining nanoparticles in water or organic solvents, without the need for chemicals or stabilizers. The size and the structure of nanoparticles obtained by LASiS can be further manipulated by a chemical free laser processing, both with a top down or a bottom up approach. In some cases, the one step functionalization of nanoparticles is possible simply by adding the ligands to particles solution. UV – visible spectroscopy allows the monitoring of functionalization process and the estimation of particles size and aggregation. So obtained nanoparticles were studied for multiphoton absorptions, for linear and nonlinear modulation of photonic crystal pseudogaps, for surface enhanced Raman scattering labelling and for hyperthermal therapy in cancer cells.