1. Optical Density of Ge Implanted Type III Silica of various concentrations Optical Density of Ge Implanted Type IV Silica of various concentrations Optical Density of Ge Implanted Types III and IV Silica and Si Implanted Type III Silica, with a Concentration of 3x10 16 ions/cm 2 Optical Density of Ge Implanted Types III and IV Silica and Si Implanted Type III Silica, with a Concentration of 3x10 15 ions/cm 2 Optical Density of Ge Implanted Types III and IV Silica and Si Implanted Type III Silica, with a Concentration of 1x10 16 ions/cm 2 Background: Defects in the structure of silica have an effect on optical devices that depend on their ability to transmit light of various energies, such as fiber optics and Bragg gratings. An understanding of the effects and causes of such defects would lead to improved efficiency in optical devices. The purpose of this experiment is to determine the effect of germanium and silicon implantation on Type III and IV silica. Procedure: A series of Ge and Si implanted silica samples were fabricated consisting of hree groups of like concentration of implanted ions, 3x1015ions/cm2, 1x1016ions/cm2 and 3x1016ions/cm2. Germanium was implanted in Type III and IV silica, while silicon was implanted in Type III silica. Ion beams with energy of 500 keV were used to implant both silicon and germanium. This implantation causes various defects in the structure of the silica, including implanted ions displacing or replacing the silicon and oxygen atoms of the silica. All samples of like concentration were implanted at the same time. The optical absorption was measured at wavelength intervals of 1 nm from 1.8 eV to 6.5 eV using a dual beam (Cary 5) spectrometer with an unimplanted sample in the reference beam. Hence, all absorption measurements represent the difference between implanted and unimplanted samples and are reported in units of optical density. The absorption was measured at two different positions on the sample Results: Each absorption band is characteristic of the defects in the substance. To determine the effect of germanium and silicon implantation, optical spectra of the twelve samples were measured. Optical spectra show strong peaks on the samples ranging from 5eV to 6eV, depending on the implantation concentration and the type of silica. Silicon has a peak at 5.03eV that does not shift. Germanium implanted Type III silica, on the other hand, has peaks at 5.11eV, 5.18eV and 5.19eV, at concentrations of 3x10 15 ions/cm 2, 1x10 16 ions/cm 2 and 3x10 16 ions/cm 2, respectively. Germanium implanted Type IV silica has peaks at 5.12eV, 5.13eV and 5.22eV. The optical density of all three silica samples types increases with concentration. The germanium for like dose exhibits higher optical density in all cases that the silicon implanted samples. Ge implanted type IV silica exhibits higher absorption for like doses compared to the Type III silica. The peaks in each sample show a shift in energy between each dose. The ratios of the optical density of the peak to the optical density of the sample at 6.00eV show this shift. This ratio shows how the peak shifts due to implantation concentration. In all three cases, there is an increase in the ratio from 3x10 15 ions/cm 2 to 1x10 16 ions/cm 2. Then the ratio decreases when the dosage is increased to 3x10 16 ions/cm 2 ; however, the ratio is still higher than the value for 3x10 15 ions/cm 2. Conclusion: The shape of the absorption curves as well as the magnitude of absorption was observed to be dependant on the type of silica implanted as well as the ion species implanted. These results indicate a variation in the formation of intrinsic defects depending on silica type and ion species implanted. Optical Density of Ge Implanted Type III and Type IV Silica and Si Implanted Type III Silica David Coss and Robert Magruder Department of Physics, Belmont University