Topological pruning enables ultra-low Rayleigh scattering in pressure-quenched silica glass

Silica glass is the most indispensable material in optical communication applications due to its superior optical properties. The transmission loss of silica glass has been reduced over the past 30 years by continuous efforts toward decreasing density fluctuations by lowering of fictive temperature, e.g., through improvements in processing or doping. A recent study has shown that shrinkage of structural voids by hot compression is a promising way to further decrease the loss. However, an atomic understanding of the pressure effect is still lacking. Here, using molecular simulations, we connect the void shrinkage to topological pruning of silica network. Two physical models predict that the Rayleigh scattering loss of pressure-quenched silica glass can be reduced by >50% when the glass is quenched at an appropriate pressure (4 GPa in our simulation). Our studies are consistent with available experimental results and demonstrate topologically optimized structure can give desirable properties for optical applications of silica as well as other glasses with similar network structure.