  One-step laser generation of Au elongated nanoparticles (NPs) and their
successive fragmentation and agglomeration are experimentally studied for the
first time. In the present work, laser-assisted formation of Au elongated
nanoparticles by ablation of a solid Au (99.99%) target in water was done using
a ytterbium-doped fiber laser sources with pulse duration of 200 ns and pulse
energy of 1mJ. Extinction spectrum correlating with TEM shows the appearance of
absorption signal in red region and near IR-spectrum that corresponds to
longitudinal plasmon resonance of electrons in elongated Au NPs. In addition,
generated elongated Au nanoparticles were exposed to pulsed laser beam with
various pulse energy and laser exposure time. It was found that at early stages
of irradiation NPs agglomerate as the NPs chains with size of order of 1
micrometer long. Further laser exposure results in fragmentation of these
chains. Possible processes of laser-assisted formation of elongated Au NPs in
aqueous solutions of calcium chloride and their subsequent interaction with
pulsed laser irradiation are discussed.
