Luminescence properties of laser-induced silver clusters in borosilicate glass

This paper describes the luminescence properties of small silver clusters formed by laser treatment of silver-doped borosilicate glass. Using irradiation by a Nd:YAG nanosecond laser system operating at the fourth harmonic wavelength (266 nm), areas are formed in the glass samples that emit bright luminescence peaking at about 600 nm when excited by UV light in the spectral range 300–390 nm. The influence is presented and discussed of the glass composition and the laser processing parameters on the emission characteristics. It is further shown that the luminescent properties are affected by the fluence of the excitation source, namely, a complete quenching of the emission is achieved above a certain value. The luminescence of the irradiated areas is explained by the formation of Ag clusters due to irradiation-induced reduction of Ag ions and increased atom mobility resulting from the local heating. The limited stability of the luminescent areas upon UV radiation can be related to heat-induced cluster decomposition and re-oxidation. The results obtained provide a new insight in the optical properties of noble-metal nanostructures and could form the basis of fabrication of complex optical systems and luminescent component used in the study of, e.g., biological systems.