Basic Researches On Visible And Near Infrared Laser Glasses

Laser technology is the greatest invention of the twentieth century, has taken a profoundimpact on the development of modern science, technology and social economy. Due to itsown set of advantages, laser glasses have been widely used in the laser technology. However,with developing of laser technology, more diverse and higher quality laser glasses should tobe developed to achieve high power, new wavelength laser output.This dissertation is focused on the basic study of laser glasses. The dissertation iscomposed of introduction, measurement methods and relative theory, visible fiber laserglasses, bismuth doped glass, rare-earth doped phosphate glass fiber, femtosecond directwriting waveguide and fiber gratings in rare-earth doped phosphate glass and fiber.Chapter1introduces the definition of laser glass and research progress of visible fiberlaser, bismuth doped material and bismuth doped fiber laser.Chapter2introduces the sample preparation and experiment measure methods, J-O andMcCumber theorys, non-radiative mechanisms of non-raditive transitions of rare earth ions.In chapter3, we systematically study the spectroscopic properties of Sm3+, Pr3+andTb3+-doepd oxide glasses. We comparatively study the spectroscopic properties of Pr3+-dopedphosphate, silicate and tellurite glasses. The emissions from Pr3+-doped boro-phosphate,boro-germo-silicate and tellurite glasses show different decay behaviors and can be wellexplained by multiphonon relaxation theory. We demonstrated that Sm3+-doped phosphateglass is more suitable as gain medium for visible fiber laser, since its absorption andstimulated emission cross sections lager than Sm3+-doped other three oxide glsses, and alarger magnitude than Sm3+-doped silica glass fiber. For green fiber laser, Tb3+-dopedphosphate is the most suitable gain medium, since no concentration quenching were observedin Tb3+-doped phosphate glass when Tb3+concentration is up to15mol%. And thefluorescence quantum efficiency of10mol%Tb3+-doped glass is up to78%.In chapter4, we study the dependence of NIR luminescence of a Bi-doped silica glasson the excitation wavelengths in the range of280-980nm. The emission peak of the Bi-dopedsilica glass shows a complex change between1120nm and1270nm when the excitationwavelength change from280nm to980nm. We assign NIR emissions at1120nm and1270 nm to3P1→3P0transition of Bi+and2D3/2→4S3/2transition of Bi0, respectively. Tentativeenergy level diagrams for Bi+and Bi0are proposed according to the absorption spectra andexcitation spectra of the glass sample. The proposed model can well explain the observedluminescent phenomena.Chapter5describes designing and fabrication methods of rare earth dopedmulti-component glass fibers. We fabricated Tb3+-doped phosphate glass fiber by usingrod-in-tube method. The optical loss at1310nm of obtained fiber is measured to be3.18dB/m. And we also designed and fabricated Tb3+, Nd3+-doped phosphate glass fibers by usingstack-and-draw method. The optical losses at1310nm are10.6dB/m and6.453dB/m,respectively. We fabricated fiber grating structures in rare earth doped phosphate glass fiberby femtosecond direct writing method. We also fabricated waveguide in rare earth dopedphosphate laser glass, and we successfully couple the single and multi mode laser into thewaveguide.