Ag nano-composite glasses synthesized by swift heavy ion irradiation

In the present work, we have used swift heavy ions (SHI) irradiation and post irradiation annealing to synthesize Ag nanoparticles in fused silica. Fused silica samples deposited with 15 nm of Ag film were irradiated using SHI beam of 120 MeV Ag9+ ions at different fluences and post irradiation annealing was done at 500 °C in air for 30 min. The samples were characterized using UV-vis absorption spectroscopy, Rutherford Backscattering Spectrometry (RBS), GAXRD, Transmission Electron Microscopy (TEM), and open aperture z-scan measurements. The signature of Ag nanoparticles was observed in optical absorption spectra and the average size of the Ag nanoparticles was estimated using Mie's theory. The size of the nanoparticles (~3 nm) was also confirmed from the GAXRD and TEM measurements. RBS results for Ag/SiO₂ irradiated with the fluence of 5 x 10¹³ ions/cm² shows the decrease in slope at the interface of the Ag profile, indicating a partial mixing at a fluence of 5 x 10¹³ ions/cm². Open aperture z-scan measurement of Ag/SiO₂ SHI irradiated sample after annealing shows a saturation behavior, indicating that the sample is optically non-linear. The sample shows saturation behavior but does not show optical limiting behavior, which indicates that the size and number density of nanoparticles are low. The ability to control the particle size using ion beam technique as a function of fluence and observed nonlinearity results provide concrete evidence that Ag nano composite glasses can be used in nonlinear and optical limiting application.