METHOD FOR LOCAL CRYSTALLISATION OF LANTHANUM BOROGERMANATE GLASS Russian patent published in 2016 - IPC C03C3/253 

FIELD: optics.

SUBSTANCE: invention relates to a method of growing microcrystalline channels in transparent and coloured glass under action of laser beam for tasks of integral optics. Invention enables to obtain crystalline lines with the help of a femtosecond laser in lanthanum borogermanate glass with lower pulse repetition frequency. This is achieved by local crystallisation of lanthanum borogermanate glass, including radiation with femtosecond laser beam focused in the glass volume, which consists of two phases: phase of crystal seed formation with fixed beam and phase of drawing crystal line from seed by beam, which is moved at constant speed. Femtosecond pulse repetition frequency is set in the range of 9-100 kHz for formation of the seed and set frequency of 5-100 kHz for formation of crystalline line, pulse energy is changed from 16 to 120 mcJ, beam focusing depth varies from 50 to 300 mcm. Sample is put into the furnace and is exposed to focused laser beam of glass composition, mol %: La₂O₃ 24.5-25.5, B₂O₃ 24.5-25.5, GeO₂ 49.5-50.5.

EFFECT: invention enables to obtain crystalline line with the help of a femtosecond laser in lanthanum borogermanate glass with lower pulse repetition frequency.

1 cl, 5 dwg, 3 ex