Fabrication and optical characterization of near UV-laser crystals using low-symmetry crystal field

使用低对称性晶体场的近紫外激光晶体的制造和光学表征

基本信息

批准号：
10650659
负责人：
KODAMA Nobuhiro
金额：
$ 0.58万
依托单位：
AKITA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650659/
关键词：
Spectrocopy Crystal field Laser Single crystal Crystal growth Structure analysis

项目摘要

We have grown CeィイD13+ィエD1-doped fluorides [BaMgFィイD24ィエD2, CaNaYFィイD26ィエD2] and oxides [melilite-type crystals AィイD22ィエD2BィイD23ィエD2OィイD27ィエD2(A=Ca, Y ; B=Al, Si)] which are candidates for tunable laser materials in the near UV and violet regions. In order to widely spread phosphors in the UV and visible regions, we have studied the optical characterization of these crystal and the effects of the strength and low-symmetry of the crystal field in the associated anion coordination polyhedron. The results of this study are summarized as follows.1. The lowest energy and the center of the gravity of the ィイD12ィエD1D excited state energy levels may be explained by the nephelauxetic effect, lowering symmetry caused by distortion, and size of the annion-coordinate polyhedra of the CeィイD13+ィエD1 in fluoride and oxide crystals.2. Broad photoluminescence in the near UV and violet regions is observed in CeィイD13+ィエD1-doped melilite CaィイD22ィエD2AlィイD22ィエD2SiOィイD27ィエD2 and CaYAlィイD23ィエD2OィイD27ィエD2. The p … More hotoluminescence spectra for these crystals are inhomogeneously broadened by the substitutional disorder. The lowest peak energies of the absorption bands of CeィイD13+ィエD1 in those crystals are coincident with the third harmonic (355nm) of a YAG laser. A new phosphor CeィイD13+ィエD1-doped BaMgFィイD24ィエD2 crystal was grown. The different optical spectra of CeィイD13+ィエD1 in the UV region are assigned to be due to regular and perturbed CeィイD13+ィエD1 site in the crystal. The energy level of the lowest 5d excited state of CeィイD13+ィエD1 in the BaMgFィイD24ィエD2 crystal is coincident with the fourth harmonics (266nm) of a Nd : YAG laser.The BaMgFィイD24ィエD2 : CeィイD13+ィエD1 and CaィイD22ィエD2AlィイD22ィエD2SiOィイD27ィエD2 : CeィイD13+ィエD1 crystals are expected to be new laser materials with a high gain and wide tuning range between the UV and near UV regions.3. UV excitation or infrared femtosecond laser excitation of CeィイD13+ィエD1-doped melilite crystals CaィイD22ィエD2AlィイD22ィエD2SiOィイD27ィエD2 and CaYALィイD23ィエD2OィイD27ィエD2 produces long-lasting phosphorescence besides intrinsic CeィイD13+ィエD1 luminescence with short lifetime (40ns). The phosphorescence persists for not less than 1 h after removal of the irradiating light. The long-lasting phosphorescence may be explained by a model of electron-hole recombination at CeィイD13+ィエD1 sites caused by hopping motion, which occurs by a thermally activated process. This is first observation of long-lasting phosphorescence of CeィイD13+ィエD1. This new optical function will be useful in the fabrication of spontaneously disappearing image pattern and time-limited three-dimensional optical memory devices. Less

我们生长了Ce-D13+D1掺杂氟化物[BaMgF-D24-D2、CaNaYF-D26-D2]和氧化物[黄长石型晶体A-D22-D2B-D23-D2O D27D2(A=Ca, Y; B= Al, Si)]是近红外可调谐激光材料的候选材料为了在紫外和可见光区域广泛传播荧光粉，我们研究了这些晶体的光学特性以及相关阴离子配位多面体中晶体场的强度和低对称性的影响。本研究的主要内容总结如下： 1．激发态能级的最低能量和重心可能是由云腾效应引起的对称性降低来解释的。氟化物和氧化物晶体中CeiiD13+ieD1的阴离子配位多面体的畸变和尺寸。2．在CeiiD13+ieD1掺杂的黄长石Ca D22D2AlD22D2SiOD27D2和中观察到在近紫外和紫光区域的宽光致发光。 CaYD23D2OD27D2。这些晶体的 p… More 热致发光光谱因取代无序而不均匀展宽，这些晶体中 CeD13+D1 的吸收带的最低峰值能量与 YAG 激光器的三次谐波 (355nm) 一致。荧光粉CeD13+D1掺杂BaMgF2D24D2 晶体在紫外区的不同光谱归因于晶体中 CeD13+D1 位点的规则和扰动。BaMgFD24D2 中 CeD13+D1 的最低 5d 激发态能级。晶体与四次谐波一致BaMgF D24D2 : CeD13+D1和CaD22D2AlD22D2SiOD27D2 : CeD2 D13+D1晶体有望成为新型激光材料，具有高增益和宽调谐范围的紫外和近紫外区。 3．紫外激发或CeD13+D1 掺杂的黄长石晶体 CaD22D2AlD22SiOD27D2 和 CaYALD23D2OD27D2 的红外飞秒激光激发除了产生短寿命（40ns）的本征 CeD13+D1 发光之外，还产生持久的磷光。去除照射光后，磷光持续不少于 1 小时。持久的磷光可以用由热激活过程引起的跳跃运动引起的电子空穴复合模型来解释。这是首次观察到 CeD13+D1 的长效磷光，这种新的光学功能将有助于制造自发消失的图像图案和。限时三维光学存储设备较少。