A surface-plasmon-resonance (SPR)-induced absorption band has been found for low-energy Ti+ implanted (subplanted) into single-crystalline SiO2 at specific substrate temperatures. The observed SPR absorption band is in the 650–850 nm wavelength range, i.e., in the visible (red) and near-infrared regions, indicating the formation of Ti nanoparticles in the subsurface layer of the SiO2 matrix. This was confirmed by calculations based on the Mie scattering theory. The SPR absorption band becomes distinguishable only at temperatures ⩾600 °C and reached its maximum at 800 °C (1/2Tm of elemental Ti). The intensity is significantly reduced at a temperature of 1000 °C (2/3Tm). The evolution of the SPR absorption with substrate temperature is discussed.

The linear optical absorption properties of a titanium nanoparticle composite formed by implantation of low energy Ti ϩ into single crystal SiO 2 are reported. Evolution of a surface plasmon resonance ͑SPR͒ induced by the formation of a metal nanoparticle composite is studied as a function of ion dose. At an implantation temperature of 25°C, the threshold dose for the appearance of the SPR is ϳ3.5ϫ10 16 ions/cm 2 , indicating that spontaneous nucleation and clustering of titanium nanoparticles in SiO 2 occurs at ϳ3.2ϫ10 22 ions/cm 3 peak concentration of implants. The average particle size and volume fraction are dependent on the ion dose. The correlation of the optical response, i.e., the intensity and frequency of the observed SPR, with the nucleation/clustering of the metal nanoparticles is discussed on the basis of Mie scattering theory and Maxwell Garnett theory.