Time-resolved Spectral Analysis Of The Spectrum System Design And The Rare Earth Fluoride Single Crystals And Rare Earth Polymer Materials

This thesis mainly talks about the time resolved spectroscopy technique and the spectroscopic properties of rare earth fluoride crystals and polymers. The exact definition of luminescence is confirmed, and an overview of the principles and current research on the rare earth luminescence are given in the first section.The basic principles of pulsed fluorimetry and phase fluorimetry are detailed analyzed. The TCSPC (Time Correlated Single Photon Counting) and Stroscopic, the most popular techniques of present commercial time resolved spectroscopy systems, are discussed. A delay controller and linear gate devices are designed on the basis of improved Stroscopic technique. Using a nano-second pulsed Nd:YAG laser as excitation light source, a time resolved spectroscopy system with which the delay and window both adjustable (0.1μs to 100ms scale with 0.1μs step) are built up. In this system, the lifetime measurement can also be conducted up to a 0.1μs precision. We used a K₂YF₅∶Nd³⁺ single crystal sample here to demonstrate the system performance.The low temperature (around 10K) selected excitation spectroscopy and lifetime measurement are performed here to obtain experimental spectroscopic properties of LiKGdF₅:Er³⁺,Sm³⁺ single crystal. On the analysis of free-ion and crystal field theories of rare earth ions, the energy level scheme simulation of Er³⁺ and Sm³⁺ are carried out, which gave out a very good fitting deviation. The vacuum ultraviolet spectroscopy experiments of LiKGdF₅:Er³⁺,Sm³⁺ single crystal are conducted. With the investigation of the experimental results, the quantum cutting phenomena is observed and discussed.