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In this paper we report the linear and non-linear optical properties of metallic nano-clusters in α-Al2O3 fabricated by ion implantation (from 2 to 8×1016 ions/cm2). Thereafter, the samples were annealed at temperatures from 600 to 1100 °C in oxidising, reducing atmospheres. Once spherical nano-particles were synthesized, the samples were further irradiated with Si+++ with different energies and fluences to control the achieved anisotropy. As a result of the ion implantation mostly F+ color centers were formed. After thermal annealing they capture an electron to form F centers or combine to form a F2+ center. Also, the photoluminescence signal from Al+ interstitials appears. Regarding the non-linear optical response, the spherical-like Au nano-crystals embedded in sapphire show a positive non-linear absorption at 355 nm and negative non-linear absorption at 532 nm, which shows saturation when increasing the incident irradiance. They also present positive non-linear refraction at 532 nm, which is null at 355 nm. For the anisotropic systems, a larger birefringence than natural values was measured in the visible range by ellipsometry means.© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only. |
