An additive, preferably in the form of metal nanoparticles or nanodomains, greatly improves a laser-based method and system for inducing optical breakdown. The use of ultrashort laser pulses to induce laser-induced breakdown (LIB) in metal nanoparticles or nanocomposites makes it possible to reduce significantly the threshold laser energy required for LIB. Such nanoscale (submicron) metallic particles allows one to control the LIB process. The nanoparticles can be synthesized so as to target specific biological structures or tissues (dendrimer nanoparticles are one system for which this has been demonstrated). This opens up the possibility of performing LIB for targeted cancer treatment or microsurgery.