Investigation and Control of Ultrafast Laser-Induced Nanoscale Patterns in Bulk Fused Silica

摘要

Refractive index changes in a-SiO_2 consist of positive index variations or regular nanoscale patterns. We spectroscopically reveal the electronic and structural transformation of glass in the self-organized structures, indicating bond breaking and oxygen deficiency. We equally propose a method of real time control of nanogratings formation under the action of ultrashort laser'pulse with variable envelopes. Application as polarizing optical devices is discussed.