Fig. 1. (a) Typical low magnification of the nano-particles by the laser ablation of the pure Au metal in the solution. The inset shows the enlarged TEM image of the individual Au nano-spheres. (b) The HRTEM image of the Au nano-spheres. (c) The representative low-magnification TEM image of the Au nano-particles fabricated by unfocused laser beam irradiation of Au nano-spheres with a power density of 1.5  GW/cm2. The inset in panel (c) shows the typical tadpole-shaped Au NMs. (d) The HRTEM image of the tadpole-shaped Au NMs.

Fig. 2. (a) Representative low-magnification and (b) enlarged TEM images of the tadpole-shaped Au NMs by laser irradiation of Au nano-spheres with a power density of 3  GW/cm2, respectively.

Fig. 3. Schematic growth of the tadpole-shaped Au NMs via the laser fragmentation of the individual Au nano-sphere in liquid.

Fig. 4. (a) Curve of the mean length of the tail in tadpole-shaped Au NMs versus the laser power density. (b) The LSPR absorbance spectrums of the Au nano-spheres and tadpole-shaped Au NMs.