Ultrafast laser fabricated Nanostructures and Nanoparticles: Characterization, Spectroscopy and Applications

Ultrafast laser induced surface nanostructures and nanoparticles were fabricated on different metal semiconductor targets through ablation in various liquid media. Surface morphological information accomplished from the field emission scanning electron microscope (FESEM) data demonstrated
the diversities of ablation mechanism in each case. Fabricated nanostructures were utilized exultantly to investigate the surface Plasmon (localized and propagating) mediated enhancements of different analytes using surface enhanced Raman scattering (SERS) studies. Multiple utility of these substrates were efficiently demonstrated by collecting the SERS data of different secondary explosive molecules such as 5-amino-3-nitro-1,2,4-triazole and trinitrotoluene on different days which were weeks apart. The generated Copper NPs demonstrated fluorescence enhancement of corroles molecules at lower concentration levels. Moreover, Ultrafast excited state dynamics and nonlinear optical properties of colloids were investigated using pump-probe and Z-scan techniques with 50 fs and 2 ps laser pulses, respectively. The observed decay dynamics and large nonlinearities, suggesting that the colloidal NPs can be utilized for photonic devices.