Linear and nonlinear optical absorption in copper nanocluster-glass composites

Copper nanoclusters have been formed in fused silica glasses under 100 keV and 200 keV Cu+ ion implantations. UV–Vis spectroscopy measurements have revealed prominent linear absorption bands at characteristic surface plasmon resonance (SPR) frequency signifying the appreciable formation of copper colloids in glass matrices even without thermal treatments. Ion-induced colloid formation in glasses without thermal treatments is probably the first time observation in the present study. Subsequent annealing of the implanted samples has resulted in the further enhancement of the absorption bands. Formation of copper nanoclusters without thermal annealing can be attributed to the relatively high mobility of copper atoms even at ambient conditions. The transmittance measurements made by Z-scan technique have revealed saturable absorption signifying the nonlinear optical responses of the metal nanocluster-glass composites.