Tl2S–Ga2S3–GeS2 glasses for optically operated laser third harmonic generation

We have shown a possibility to apply Tl2S–Ga2S3–GeS2 glasses as an effective photoinduced third harmonic generation materials. As a photoinducing beam, the 200 mW green laser at 532 nm was used. The 15 ns pulsed Nd:YAG laser with power density tuned up to 800 MW/cm2 was used. Glass-formation region in the quasi-ternary system Tl2S–Ga2S3–GeS2 was investigated by quenching molten alloys from 1300 K. The minimum concentration of the glass-forming agent GeS2 is 30 mol%. Characteristic thermal parameters and optical absorption spectra of the glasses of the system were investigated. The variations of the bandgap energy were determined. It is crucial that the photoinducing beam was excited in the bulk of the materials and the output third harmonic generation signal was observed for the 355 nm beam formed near the surface.