Synthesis And Optical Properties Of Indium Based Chalcohalide Glasses And Rare Earth Doped Oxyfluoride Glasses

The first part of the thesis mainly emphasized on the glass formation, third-order nonlinearity, and emission properties of the Indium-based chalcohalide glasses. For the presence of relatively heavy atoms (In), these glasses have the lower maximum phonon energy and higher refractive index. Thus higher radiative emission rates and larger nonlinearity could be yielded. The main results are shown as follows.A fairly large glass-forming domain of the GeSe2-In2Se3-CsI glasses is determined. These glasses show excellent transparency from 0.6 to 16μm. With the addition of CsI, the Tg decreases, the visible absorption edge shifts toward the short wavelength region. Correspondingly, the color of the samples varies from black through red to orange following the increased content of CsI. Raman spectra show that [GeSe4] and [InSe4.xIx] tetrahedral are the major structural units in the glass network. The obtainedχ(3) and n2 of 70GeSe2-20In2Se3-10CsI glass are as large as 10.07×10-12esu and 6.5×10-18m2/W, respectively, more than twice that of As2S3 glass. We have shown that the n2 variation may be related to the total number of [GeSe4] and [InSe4] tetrahedral units.Bright red emission in the Tm3+ ions doped GeS2-In2S3-CsI chalcohalide glasses pumped by an 808 nm near IR high power laser diode was observed for the first time. By codoping different concentration of Er3+ ions, emission can be tuned from monochromatic red to green, which is significant for their applications such as light emitting displays, lasers, and optoelectronic devices. The analysis demonstrates that the intensive red and green luminescence is generated from two-photon absorption process. The Er3+ ions codoping, higher concentrations of Tm+ ions and/or indium favor the 700nm red emission.Broadband emission extending from 1.35 to 1.7μm with the full width at half-maximum (FWHM) of-160 nm was obtained at room temperature in a 0.1 mol% Er2S3 and 0.5 mol% Tm2S3 co-doped 70GeS2-20In2S3-10CsI glass sample under 808 nm excitation. The emission spectra and fluorescence decay curves indicate that the Tm3+-Er3+ ions co-doping suppressed the cross relaxation between Tm-Tm or Er-Er ions due to formation of mixed bonds and therefore a decrease of non-radiation transition probability among each rare earth's energy levels.The second part works on the downconversion emission in the Pr3+/Yb3+ ions codoped oxyfluoride glasses. Near-IR downcoversion emission with the 6% quantum yield has been realized in the Pr3+/Yb3+ ions codoped 40SiO2-30Al2O3-18Na2O-12LaF3 glass. Comparing the absorption and emission spectra of the glasses with that of the glass ceramics, the Pr3+ ions have the priority to enter the LaF3 crystals due to the similar crystal lattice, thus the energy transfer efficiency decreased in the present glass by crystallization. The enhancement of the near IR emission is due to the suppressed non-radiative transition and the enhancement of the pumping efficiency.