Crystal Growth And Characterization Of Dysprosium Ion Doped Yttrium Aluminate Series Crystals

Crystals are solid materials with long-range order,and functional crystals are the medium for the transformation of various forms of energy such as force,heat,electricity,magnetism,light,and sound,and are one of the basic materials for the development of modern science and technology.Functional crystals and their devices play a fundamental and pioneering role in modern science and technology,and the contemporary science and technology revolution has benefited from major breakthroughs in the field of functional crystals and their devices.Laser crystals are an important functional crystal material and one of the effective media for realizing laser output.Laser technology,along with computer technology,semiconductor technology,and atomic energy technology,has been called the"four new inventions"of the last century.The yellow laser（560～600 nm）,which is sensitive to the human eye,coincides with the characteristic absorption peaks of melanin,hemoglobin,and chromophores,and is the basic light source for laser display and laser illumination,and has important needs in medical,life,and research fields.The current effective way to obtain yellow laser light is through processes such as sum frequency,Raman,or self-frequency-doubling,which involve both laser and nonlinear processes and need to involve the compounding of two to three crystals,making the design and theoretical analysis relatively complex.In this thesis,the following work was carried out to provide substrate crystal materials that can generate yellow laser light in response to the demand for a wide range of applications of yellow laser light.（1）By analyzing the characteristics of laser-activated ions and matrix crystals,Dy³⁺ion-doped YAP crystals were selected as the object of study,and Dy:YAP crystals with different concentrations of doping were grown using the Czochralski method.（2）The elements affecting the quality of the crystal growth by the Czochralski method were analyzed.The crystal quality was improved by adjusting the temperature field,rotation and pulling rate,and seed crystal orientation,and the largest size of Dy:YAP crystals were finally obtained.（3）The thermal properties of Dy:YAP crystals were characterized,and the pattern of their thermal properties with concentration was summarized,confirming that the YAP series crystals have excellent thermal properties and possess advantages in laser applications.（4）The optical properties（including absorption and emission spectra）of Dy:YAP crystals were measured.The absorption peak at 450 nm and emission peak at 570 nm confirmed the suitability of Dy:YAP crystals for pumping with blue LD to obtain yellow laser.The spectral properties of Dy:YAP crystals doped with different concentrations were analyzed comprehensively,and the optimal doping concentration of 1at%was obtained.（5）A warm white light output with a color temperature T_c=4000 K and a fluorescence quantum yield of 26.7%was achieved with a simple optical path design using Dy:YAP crystal.This thesis has the following innovative features for the study of dysprosium ion-doped yttrium aluminate crystals:（1）Based on the analysis of the characteristics of the laser-activated ion energy level,the current research and development status of blue light LD,and the characteristics of the substrate material,Dy³⁺ion-doped YAP crystals were selected as the research object to directly pump Dy:YAP crystals with blue light LD to directly generate yellow light laser to enrich the way to obtain yellow light and simplify the design of yellow light devices.（2）The growth conditions and processes of Dy:YAP crystals with different doping concentrations are systematically studied,and the effects of doping concentration on crystal growth and quality are summarized.The basic properties such as thermal and optical of this series of crystals are systematically studied,and the variation of the basic properties of the crystals with concentration and its laws are summarized and elucidated,which provides the basis for the subsequent research on Dy:YAP while having practical innovation.（3）In the fluorescence experiments on Dy:YAP series crystals,the color coordinates of the mixed white light and the color temperature were adjusted by adjusting the residual blue light of the pump source,which is a methodological innovation.