This work focuses on the investigation of plasmonic Gold (Au) and Silver (Ag) nanoparticles (NPs) by using optically induced local thermal dewetting technique and their applications. Firstly, Au and Ag NPs are fabricated by a thermal annealing method using a hot oven. This technique allows obtaining Au and Ag NPs, which are randomly distributed in a large area. The NPs sizes and properties are controlled by annealing conditions, such as annealing temperature and duration. Plasmonic properties of Au and Ag NPs are experimentally characterized and compared with the simulation ones performed by the FDTD method. These large-area Au and Ag NPs are demonstrated to be useful for applications in fluorescence enhancement and random laser. Secondly, we demonstrate a robust way to realize desired plasmonic nanostructures by using a direct laser writing method. This technique bases on optically induced local thermal effect allowing the realization of NPs at a small area, i.e. focusing area. By moving thus the laser spot, any desired plasmonic structure can be realized. The NPs sizes and distributions can be controlled by exposure doses (laser power and exposure time) and moving trajectory of the focusing spot resulting in different reflection or transmission colors. By focusing a continuous-wave laser at 532 nm on Au films having 50 nm thickness, we demonstrated for the first time the direct fabrication of plasmonic nanoholes array. These fabricated structures are demonstrated to be very potential for many applications such as data storage, color nanoprinter, fluorescence enhancement, and plasmonics based random laser.