Local phase-structure modification inside of lithium silicate glass by combined double-wavelength laser action

The process of local structure modification inside of lithium silicate glass under the combined laser action of two different wavelengths is considered. The first step is laser irradiation of ultrashort laser pulses with 532 nm wavelength, which is used to create of nucleation centers inside of the optically transparent glass. The crystallization of the structural modification areas was carried out by a photothermal action of CO₂ laser radiation with a 10.6 μm wavelength. The range of crystallization temperatures was defined and the kinetics of the phase transformations of the modified regions inside of the glass were studied. Duration of crystallization was about 10 min with a slow heating and 25 s at the fast heating to crystallization temperature.