| 题名 | 掺稀土锗酸盐玻璃光纤中红外光谱与激光性能的研究 |
| 作者 | 徐茸茸 |
| 学位类别 | 博士 |
| 答辩日期 | 2012 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 张军杰 |
| 关键词 | 2~3µ m，中红外光谱与激光，稀土离子掺杂，锗酸盐玻璃光纤 |
| 其他题名 | Mid-infrared spectroscopic properties and laser performance of rare earth ions doped germanate glasses and fibers |
| 中文摘要 | 2~3µm波段的中红外激光在光通讯、医疗、环保和国防等领域有着重要的应用前景，激光技术的发展在很大程度上依赖于高性能激光材料的发展，因此激光材料是激光技术发展的核心和基础。本论文的主要目的是研究适用于~2µm激光输出的玻璃和光纤，探索适用于~3µm发光的新型玻璃材料。通过对锗酸盐玻璃组分的探索和掺杂离子浓度的优化，制备出了一种适用于~2µm发光的玻璃材料，在Tm3+单掺锗酸盐玻璃中实现了百毫瓦级的~2µm激光输出。 论文第一章首先综述了2µm和3µm稀土离子掺杂玻璃光纤的发展与应用，概括了锗酸盐玻璃材料的基本特点及锗酸盐玻璃光纤的研究进展，然后提出了本论文主要的研究内容和思路。 论文第二章主要介绍了锗酸盐玻璃和光纤的制备方法、性质测试、光谱理论计算和分析方法等。 论文第三章研究了不同GeO2含量对锗酸盐玻璃的热学、结构及2µm光谱性能的影响。随着GeO2含量的增加，非桥氧减少，玻璃结构变得紧凑，转变温度也随之升高，最大声子能量从838cm-1升到855cm-1。结果表明，GeO2-Ga2O3-BaO /BaF2-Na2O-La2O3（G1）玻璃具有良好的热学性能和光谱性质，是一种实现1.8µm激光输出的理想玻璃基质材料。以G1玻璃为基础，系统研究了Tm2O3掺杂锗酸盐玻璃的热学性能和光谱性能。Tm2O3掺杂的最佳浓度值为3wt%，在1.8μm处的发射截面为9.3×10-21cm2。研究了Yb3+/Ho3+双掺锗酸盐玻璃在2μm波段的发光性能及能量传递过程。当Yb2O3 和Ho2O3浓度分别为5mol%和1mol%时，2μm荧光强度最强。Ho3+:5I7→5I8跃迁的发射截面为8.6×10-21cm3。反向能量传递系数CA-D是正向能量传递系数CD-A的0.054倍，说明Yb3+能有效地将能量传递给Ho3+离子。研究了锗酸盐玻璃中Ho3+离子2μm光谱性质。分别对Ho3+进行直接泵浦和利用Tm3+离子做敏化剂间接泵浦，荧光光谱数据表明，Tm3+/Ho3+双掺锗酸盐玻璃更有利于获得高强度的2μm发光。研究了Ho3+/Tm3+/Er3+三掺锗酸盐玻璃2μm的发光以及离子之间的能量转移过程。Ho3+可以有效地被Tm3+和Er3+离子敏化，Tm3+:3F4→Ho3+:5I7是Ho3+离子的主要敏化方式。Er3+离子通过Er3+:4I13/2→Tm3+:3F4过程，有效地将能量传递给Tm3+离子。 论文第四章首先研究了不同Bi2O3含量锗酸盐玻璃的热学性能、玻璃结构和3µm光谱性质。当Bi2O3含量为10mol%时，锗铋酸盐玻璃在2.7μm的发光最强，Er3+离子的最大发射截面为7.17×10-21cm2。以锗酸盐玻璃为基础，研究了Cr3+离子对Er3+离子在2.7μm发光的影响和能量转移过程。当Er3+和Cr3+离子双掺浓度分别为2mol%和0.2mol%时，2.7μm的荧光强度最大。研究了在锗酸盐玻璃中Yb3+离子作为敏化剂对Er3+离子2.7μm发光的影响。Yb3+离子引入极大的提高了980nm的泵浦效率，Er3+/Yb3+双掺能够有效地增强Er3+在2.7μm处的荧光强度。研究了Er3+/Pr3+双掺锗酸盐玻璃的热学性能、光学性能以及光谱性质。2.7μm附近的透过率为85%，能量转移过程(4I13/2,3H4)→(4I15/2,3F3)的效率高达95%。Pr3+离子能够有效地抑制Er3+：4I13/2能级上的粒子数，从而促进2.7μm发光。研究了Er3+/Tm3+/Nd3+三掺锗酸盐玻璃在2.7μm的发光特性。Er3+:4I11/2→4I13/2能级跃迁对应的自发辐射跃迁几率为26.61s-1，荧光分支比为28.89%。Tm3+和Nd3+离子引入能有效提高样品在808nm的泵浦效率，还通过能量转移过程有效地减少了Er3+：4I13/2能级上的粒子数，促进粒子数反转。 论文第五章以GeO2-Ga2O3-BaO/BaF2-Na2O-La2O3玻璃为基础，研究了Tm3+单掺锗酸盐块体玻璃的2μm光谱和激光性能。Tm3+：3F4→3H6能级跃迁对应的最大受激发射截面为8.7×10-21cm2，量子效率为71%，非辐射弛豫跃迁几率为0.09ms-1，表明掺Tm3+锗酸盐玻璃具有良好的光谱性能。以792nm激光二极管为泵浦源，获得了最大输出功率为346mW，斜率效率为25.6%的1.9μm激光输出。实验结果表明，掺Tm3+锗酸盐玻璃是一种具有良好发展前景的中红外发光材料。在锗酸盐块体玻璃基质的基础上，通过设计出芯心和包层玻璃的组分，利用棒管法制备了光纤预制棒，在拉丝塔中进行光纤拉制，研究了Tm3+离子掺杂锗酸盐玻璃光纤2μm光谱和激光的性能。采用不同长度的光纤进行荧光测试，和块体玻璃荧光光谱相比，荧光峰值从1.8μm红移到1.9μm，光纤光谱的荧光半高宽（FWHM）从238nm减小到210nm。由于光纤损耗较大，并未获得激光输出。在接下来的工作中重点是要进一步优化光纤组分、改进玻璃熔制工艺、棒管加工工艺和光纤拉丝工艺，以制备光学均匀性良好的光纤预制棒；其次是改进激光测试系统。 论文第六章研究了Er3+/Tm3+双掺锗酸盐玻璃在近红外通信波段的发光性能和Er3+/Tm3+离子之间的能量转移效率。Er2O和Tm2O3最佳浓度配比分别为0.2wt%和0.8wt%，此时近红外波段（1350nm-1675nm）的荧光半高宽为~138nm，荧光峰范围为1300nm-2200nm，包含了S波段1440nm-1530nm，C+L波段1530nm-1600 nm和U波段1600nm-1675nm。Er3+/Tm3+离子间能量传递效率达76%，说明了Er3+和Tm3+离子之间存在有效的能量转移过程。 |
| 英文摘要 | Mid-infrared lasers around 2~3μm have many applications in the area of optical communication, medical treatment, environmental protection, national defense, and so on. It is significant to do research on laser materials because the development of laser technology relies on them. The motivation of this study is to search novel glass hosts suitable for mid-infrared wavelength around 2~3μm laser and broadband communication system. A novel germanate glass is fabricated, which is suitable for the laser performance around 2μm. A hundreds of mW level cw bulk glass laser around 2μm is demonstrated in this germanate glass. The effects of GeO2 content on the thermal stability, structural origin and spectroscopic properties at 2μm of germanate glasses are investigated. With the increment of GeO2, the content of nonbridging oxygen comes down, the transition temperature increases，and the maximum phonon energy turns from 838cm-1 to 855cm-1. It is found that GeO2-Ga2O3-BaO/ BaF2-Na2O-La2O3 glass with good thermal stability and spectroscopic property is a promising candidate for mid-infrared laser application. Based on the glass host, thermal stability and spectroscopic property of Tm2O3 doped germanate glasses are investigated. The results show that the emission intensity of 2μm arrives the maximum when the glass doped with 3wt% Tm2O3, and the emission cross section is calculated to be 9.3×10-21cm2. The spectroscopic properties and energy transfer processes of Yb3+/Ho3+ co-doped germanate glasses are studied. The highest gain in 2μm region could be achieved from the germanate glass with 5mol% Yb2O3 and 1mol% Ho2O3. The emission cross section of Ho3+:5I7→5I8 is 8.6×10-21cm3. The energy transfer microscopic parameter is 8.11×10-39 cm6/s, and the coefficient of the forward energy transfer Yb3+→Ho3+ is 19 times of magnitude larger than that of the backward energy transfer Ho3+→Yb3+. Tm3+/Ho3+ codoped germanate glasses are also investigated, the results show that Tm3+ can efficiently sensitize Ho3+ and achieve broadband emission around 2μm. The germanate glass doped with Ho2O3, Tm2O3, and Er2O3 are investigated. The microscopic process of resonant transfer Tm3+→Ho3+ is more likely to occur in contrast with the nonresonant transfer Er3+→Ho3+, meanwhile Er3+ ions can transfer their energy to Tm3+ with high efficiency and a large coefficient. The 2.7µm emission spectra and microscopic energy transfer coefficients of Er3+-doped bismuth-modified germanate glasses are investigated. The emission intensity of 2.7µm achieves largest when the content of Bi2O3 arrives 10mol%, and the emission cross section of 2.7µm is 7.17×10-21cm2. Based on the germanate bismuth glass, spectroscopic properties of Er3+/Cr3+ co-doped glass are investigated. The intensity of 2.7µm emission becomes largest at the content of Er3+/Cr3+ as 2mol% and 0.2mol%. Emissions of the germanate glasses doped with Er3+ and Yb3+ are studied. Efficient energy transfer from Yb3+ to Er3+ is demonstrated and intense emission spectra of 2.7µm are obtained. Er3+/Pr3+ codoped germanate glass is fabricated and analyzed. The maximum transmittance around 3μm reaches 85%, and energy transfer efficiency of (4I13/2,3H4)→(4I15/2,3F3) process arrives as high as 95%. It is demonstrated that Pr3+ ions can depopulate the Er3+:4I13/2 level and enhance intensity of 2.7µm emission. Emission properties at 2.7μm from Er3+/Tm3+/Nd3+ tri-doped germanate glass are investigated. The higher radiative transition probability (26.61 s-1) and branching ratio (28.89%) of Er3+:4I11/2→4I13/2 transition give evidence of intense 2.7 μm emission. The absorption coefficient of 808 nm increases from 0.11 cm-1 (Er3+ singly doped) to 8.46 cm-1 (Er3+/Tm3+/Nd3+ tri-doped), which is demonstrated that Tm3+ and Nd3+ ions can enhance the pumping efficiency around 800 nm. Moreover, ions in the Er3+:4I13/2 level are largely depopulated by energy transfer process via Tm3+ and Nd3+, and that induces the population inversion of 2.7μm. Based on the novel germanate glass: GeO2-Ga2O3-BaO/BaF2-Na2O-La2O3, bulk glass is designed and fabricated with high optical quality. The structural origin and laser performance of thulium doped germanate glasses have been studied. Large emission cross section of Tm3+:3F4 level (8.69×10-21 cm2), high quantum efficiency of 3F4 level (71%) and low nonradiative relaxation rate of 3F4→3H6 transition (0.09 ms-1) illustrate good optical properties of the germanate glass. The room temperature laser action from the thulium doped germanate glass is demonstrated when pumped by a 790 nm laser diode. The maximum output power 346 mW and slope efficiency 25.6% are achieved. Based on the novel germanate glass, inner cladding and outer cladding glasses of the fiber are designed and fabricated. Spectroscopic properties and laser performance of Tm3+ doped germanate glass fibers are investigated. Emission spectra of fibers with different length are obtained. Compared with the emission spectra of bulk glass, the peak shifts from 1.8μm to 1.9μm, and the full width at half maximum (FWHM) decreases from 238nm to 210nm. Unfortunately, the laser performance isn’t achieved because of large loss of the fiber. It is important to improve the technology of glass melting, optical fiber preform rod fabrication and fiber drawing in the following work. Broadband near-infrared emission properties and energy transfer process are investigated in Er3+/Tm3+ codoped germanate glass. A broadband emission extend from 1300 nm to 2200 nm with the full width at half maximum (FWHM) around 138 nm is obtained in the germanate glass which codoped with 0.2 wt% Er2O3 and 0.8 wt% Tm2O3. And energy transfer efficiency from Er3+ to Tm3+ reaches 76%. |
| 语种 | 中文 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15714]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 徐茸茸. 掺稀土锗酸盐玻璃光纤中红外光谱与激光性能的研究[D]. 中国科学院上海光学精密机械研究所. 2012. |
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