Laser direct writing into PbO-Ga2O3 glassy system: Parameters influencing microlenses formation

New microlenses with potential applications in optics on the surface of the various glasses of the (PbO)(x)(Ga2O3)(1-x) system (x = 0.698-0.789) were created. The role of several parameters (chemical composition, surface roughness and exposition conditions) on the microlenses formation was investigated. The most promising composition is (PbO)(0.747)(Ga2O3)(0.253) possessing metagallates structure, which is the most thermally stable and thus this glass has the lowest value of the fragility factor. This is related to the highest threshold value of the laser power density for the microlenses formation. The highest microlenses were created for this composition. The Root Mean Square characterizing the surface roughness should be approximate to 2.8 nm. An increase of exposition time and the used laser power density led to the microlenses height rose. The threshold value of the microlenses formation decreased significantly with the increased exposition time. Certain properties of microlenses and non-illuminated surroundings of microlenses were compared. There were no structural and chemical composition changes observed using the Raman Spectroscopy and EDX analysis, respectively. The Force Spectroscopy mode and the Nanoindentation found a decrease in the created microlens stiffness and hardness by 8 and 10%, respectively. The thermal expansion is suggested as the most likely mechanism of microlenses formation.

Automated summary

(English Summary:) New microlenses with potential applications in optics were successfully created on the surfaces of glasses in the (PbO)(x)(Ga2O3)(1-x) system. The most promising composition found was (PbO)(0.747)(Ga2O3)(0.253), which showed the highest thermal stability and lowest fragility factor. The microlenses' height increased with higher exposition time and laser power density, while the threshold value for their formation decreased significantly with prolonged exposure time.