A Minireview of the Natures of Radiation-Induced Point Defects in Pure and Doped Silica Glasses and Their Visible/Near-IR Absorption Bands, with Emphasis on Self-Trapped Holes and How They Can Be Controlled

Figure 10

Growth of induced attenuation at 1300 nm in lengths of Corning single mode (SM) Ge-doped-silica-core optical fibers separately subjected to γ-ray irradiations at dose rates of 0.011, 0.45, 17, and 340 rad/s at 50°C (continuous solid curves and black squares) [53]. The small open circles are best fits to these four data sets based primarily on the fractal second-order-kinetic growth solutions given as (equation (17) of [48]) for defects (termed “Population A”) that thermally decay at ambient temperature. However, after the best-fit Population-A simulations were accomplished and found to be less than perfect, these fits were improved upon by cut-and-try additions of first one, and finally two nondecaying (dose-rate independent) populations, termed B and C. The finally optimized Population B and C growth curves are illustrated here by the correspondingly labeled dotted curves. Because these additional populations were independent of dose rate by design, the very same pair of curves had to be added to each of the four fractal-kinetic simulations comprising the dose-rate-dependent parts of the four growth curves in order to achieve the final fits, such as the ones depicted here. Figure from [48].