Investigations of nanoparticles for optical power limiting

In order to study the properties of potential mate-rials for optical limiting, i.e. the nonlinear transmit-tance of the various suspensions, we conducted experiments with short (ns) and ultra-short (ps) laser pulses in the visible and near infrared spectral region. Three different laser systems were used: A Coherent Infinity Nd:YAG laser system with a pulse duration of 3 ns, a SPECTRON SL400 Nd:YAG laser system with 7 ns, both work-ing at a wavelength of 1064 nm or 532 nm, and a HighQ picoRegen IC-2500 Nd-YLF laser system with a pulse duration of 8 ps, working at a wavelength of 1053 nm or 526.5 nm. As optical power limiting materials, we investigat-ed different kinds of carbon-based nanomaterials and metallic nanostructures suspended in a solvent. Among them, we studied the nonlinear properties of gold nanoparticles, multi walled carbon nanotubes (MWCNT), carbon black (CBS) and C60, the best known representative of the fullerene family. The nanoparticles were characterized regarding their geometry dependent linear optical properties by spectral transmission measurements and geometrical structure by electron microscopy. The nonlinear behavior of the suspensions at the interaction with short and ultrashort laser pulses is discussed.