Crystallization in PTR glass induced by irradiation of femtosecond lasers

Lithium silicate photosensitive glass doped silver is fabricated by means of high temperature melt in silica crucible.After irradiation of Ti-sapphire femtosecond laser followed by a thermo development which is photo-thermo-refractive(PTR) process,Li2O·Al2O3·3SiO2micro crystalline phase structure is observed and confirmed in the glass matrix with the help of optical microscope and X-ray diffraction.The above micro crystal is white and hexagonal structure.Variation of the refractive index in exposed parts of glass happens while almost no apparent variation occurrs in unexposed parts.So this is a process of structure change with spatial selectivity.Based on photo-indued refractive index change of glass and spatial selectivity of femtosecond lasers,it is expected that micro grating,optical waveguide,MEMS devices,optical mask,etc,can be fabricated in the glass matrix.