Electric Field And Light Induced Changes Of The Luminescent Properties In Rare Earth Doped Lanthanum Lead Zirconate Titanate Ceramics

Since the advent of the ruby laser, lasers and laser technologies advanced rapidly. Itis a milestone in laser field that the advent of full solid state lasers, because solid statelasers have more advatages over their gas and liquid counterparts, including a widerange working media, small volume and light mass. Until now, searching for an ideallaser material still plays a dominant role in the development of laser technique. Amongthe solid laser materials, lanthanum lead zirconate titanate （PLZT） ceramics attractbraod attention because of their highly transparency, wide optical window from400nmto6μm, low cost, and their electro-optic, piezoelectric, pyroelectric and photochromaticeffects. Rare earth doped PLZT ceramics exhibited excellent spectral characteristic,which is sensitive to external electric field and radiation （or illumination）. Therefore,multifunctional and tunable solid microlaser can be developed based on these effects. Inthis thesis, electric field and ultrovoilet light induced changes of upconversion,absorption and fluorescence spectrum in Er³⁺, Er³⁺/Yb³⁺, Ho³⁺/Tm³⁺singly or doublydoped PLZT ceramics were studied.This thesis details six kinds of upconversion mechanisms and J-O theory.Upconversion, absorption and fluorescence spectra in Er³⁺, Er³⁺/Yb³⁺, Ho³⁺/Tm³⁺singlyor doubly doped PLZT ceramics have been measured and characterized.External electrical field induced changes of upconversion spectrum in Er³⁺/Yb³⁺and Ho³⁺/Tm³⁺doubly doped PLZT ceramics have been investigated. A model wasproposed based on electrostriction and pyroelctric effect. Theoretically, crystal fieldtheory was applied in calculating the changes of the spectrum intensities based on thechanges of symmetry of unit cells around rare earth ions. The calculation values matchthe experimental results quite well. Some differences have been modified bytemperature.Single pass gain of532,561,633,1550nm seed light has been measured in Er³⁺doped PLZT ceramics under the action of external electric field. Theoretical analysishas been given based on sitimulated radiation and optical energy storage theory,pyroelectric and photochromatic effect have been used to explain the opticalamplification dynamics curves.Ultroviolet and visible light induced changes of upconversion, absorption andfluorescence spectrum were detected. Spectrometer has been used to measure thechanges of spectrum under395,455,630nm light source illumination on the surface of Er³⁺, Er³⁺/Yb³⁺, Ho³⁺/Tm³⁺singly or doubly doped PLZT ceramics. The J-O theory canbe used to calculate J-O strength parameters and spectral charateristics parameters.