| As a new laser host material, LiLuF4(LLF) single crystal have its advantages of good mechanical strength, low phonon energy, thermal stability, high light transmittance, and high chemical stability, etc. Lu3+ ion as one of the rare earth ions, has the similar structrue and the ionic radius. Thus LLF single crystal is good for the doping of other rare earth ions to emit different wavelengths of lasers. As an ideal mid-infrared emitting ion, Er3+ can emit mid-IR emission of 2.7μm(4I11/2'4I13/2). However, weak emission of 2.7μm was found in Er3+ single-doped materials for the reasons of the fluorescence lifetime of the second excited state 4I11/2 level is considerably shorter than that the first excited state 4I13/2 level. As an sensitizer, the doping of Nd3+ ion can decrease the population of Er3+:4I13/2 and enhanced the mid-IR emission of 2.7μm. Dy3+ ion was well known for its ability of emiting blue light around 480 nm and yellow light around 573 nm when excited by UV light. This ability make it possible for the use of Dy3+ ions in the production of white LED after a suitable host material is found for Dy3+ doped. In our work, blue light centered at 486 nm and yellow light centered at 576 nm were found in Dy3+ single-doped LLF single crystal sample. Changing of the doping of Dy3+ ions and the wavelength of pump light can improve the white light quality. Our work proved that Dy3+ single-doped LLF single crystal had its potential in the application of white LED.In the first section of this article, we make a brief introduction of the Mid-infrared Laser, LED materials, Rare Earth ions, Laser Crystals, and the Crystals’ Growth.In the second section of this article, we make a description of the growth, the polishing, and the characterization of rare earth ions doped LLF single crystal. We also make some introduction of the XRD, the absorption spectrum, the fluorescence spectrum and the fluorescence decay curves. Brief introduction of the rare earth ions’ luminescence mechanisms, energy transfer between rare earth ions, I-H model and J-O theory are also involved.In the third section of this article, we make a detailed description of the Bridgman growth of Er3+ singly and Er3+/Nd3+ co-doped LLF single crystal. Spectroscopic properties including absorption and emission spectra from visible to mid-infrared wavelength under 808 nm LD excitation were studied. The enhanced mid-infrared emission of 2.7μm of Er3+/Nd3+ co-doped LLF single crystal samples and the energy transfer between Er3+ and Nd3+ ions were described in detail. Fluorescence decay curves were used to verify the mechanism of the energy transfer between Er3+ and Nd3+ ions. In this part we can prove that Nd3+ is a good sensitizer for Er3+ in LLF single crystal.In the fourth section of this article, we report the growth of Dy3+-doped LLF single crystal by Bridgman method and demonstrate the capability of generating white light by simultaneous yellow and blue emissions of phosphorescent centers under excitation of ultraviolet light.In the last part of this article, conclusions of our research and the outlooks for future research were described. |
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