Study On Second-order Nonlinear Optical Properties Of Ge-S Chalcogenide Glasses And Their Films

For the purpose to exploit new type of second order non-linear optic glasses, Ge-As-S and Ge-Ga-S-S bulk chalcogenide glasses were prepared by traditional quench method. DSC-TG and XRD were utilized to analyze the glass-forming ability of these glasses. Transmission was done on UV-Visible Spectrophotometer. Raman spectroscopy was used to analyze the structure. Ge-Ga-S-S glass films were deposited by RF magneto sputtering. SEM was used to observe the surface and the cross section of the films. Index of refractive was derived from the ellipsometer. Raman spectroscopy and XPS were used to analyze the structure and composition of the films.Homogeneous bulk glasses of Ge-As-S and Ge-Ga-S-Se could be easily prepared. In the Ge-As-S system the UV absorption edge shifted towards the longer wavelength with the increase of As content, while in the Ge-Ga-S-Se system, with the increase of Se. And in Ge-As-S system, Ge-S and As-S were the glass formers, while in Ge-Ga-S-Se, Ge-S, Ga-S, Ge-Se, Ga-Se were the glass formers. Having been Thermally/Electrically poled, the SHG maker fringes were obviously observed. In Ge-Ga-S-Se the SHG intensity changed appreciably with the increase of Se content. Bipolar alignment model was adopted to interpret for the generation of SHG.Homogeneous films were deposited from l-10um in thickness. The compositions varied with different sputtering power and the type of the elements. XRD analysis proved that the films were still amorphous. Raman analysis indicated that the composition and structure varied from the bulk glasses in that the sputtering rate for each element was different. More Se-Se bonds formed in the films. The SHG was found in as-prepared films and the intensity of film with 20% Se was bigger then that of 10% Se films. This phenomenon indicated that the film had been poled during the fabrication, due to the influence of electric field and magnetic field.