Laser processing and monitoring of Ag photodoped patterns in GeS2 amorphous films by dual functional laser scanning micro-processing/micro-scope system utilizing UV/VIS confocal laser scanning microscope

The photodoping phenomenon of Ag is one of the light induced phenomena in GeS2 amorphous chalcogenide films. Photonic structures like wave guides and micro-optics may be possible to fabricate utilizing the refractive modulation caused by the doping process of Ag, but the practical fabrication method has not been established yet. The method to monitor the doping also has to be paid attention for precise processing. In this report, a dual functional laser scanning system integrating micro-machining and micro-scope systems is proposed. An UV laser, effective for photodoping phenomenon, is used to process the doping patterns, and a VIS laser, not influential upon the material, is used to monitor the fabricated patterns. In-situ nano scale manipulation and observation processes were possible under same setup in one system. As a typical photonic pattern, diffraction gratings of Ag/GeS2 were fabricated and optical performances were evaluated. An optical model of the light propagation in the doped layers is proposed and simulated. The mechanism for the enhanced broadening of the doped region was suggested well through the simulation. This system will open new device fabrication and help to advance the research of nanostructures and photonic crystals.