On the parameters influencing the formation of microelements in the Ge-As-S glasses by visible CW laser direct writing

CW laser direct writing was successfully performed into the Ge-As-S annealed bulk glasses having different mean coordination numbers (CN) ranging between 2.32 and 2.67. Visible light lasers operating at three different wavelengths (447, 532 and 655 nm) were used to determine the key parameters controlling the formation of microelements on the surface of studied glasses. The formation of the highest microlenses was induced for all samples by the laser operating at 532 nm, mainly due to the significant role of the optical penetration depth of the light used, which in this case was close to the sample thickness. The influence of other parameters (Tg, CTE, structural arrangement inferred from Raman spectroscopy) that could further enhance the formation of microlenses was also discussed. The microlines and microlenses array, potentially applicable e.g. as passive optical elements, were formed for the sample with CN = 2.32, which provided the formation of the highest microlenses. The created microelements were characterized by energy-dispersive X-ray analysis and force spectroscopy to detect possible changes in their relevant properties.