Yellow-to-violet, blue, and green frequency upconversions in Nd3+-doped PbWO4 single crystal
Yellow-to-violet, blue, and green frequency upconversions in Nd3+-doped PbWO4 single crystal
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DOI：
10.1063/1.2358395
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发表时间：
2006-10-15
影响因子：
3.2
通讯作者：
Jang, Kiwan
中科院分区：
文献类型：
--
作者：
Huang, Yanlin;Jang, Kyoung Hyuk;Jang, Kiwan
通过在 10 至 295 K 温度下脉冲激光激发到 (4)G(5/2)+(2)G(1)(7/2) 能级，研究了 PbWO4 晶体中掺杂 Nd3+ 离子的上转换发射特性。主要的上转换发射由 435-447 nm 波长范围内的强蓝色发射带组成，对应于 P-2(1/2)-> I-4(9/2) 跃迁。观察到位于 356-397 nm 波长区域的一些紫外波段，对应于 D-4(3/2)-> I-4(9/2)、I-4(11/2) 和 I-4(13/2) 跃迁，以及位于 525.2 nm 处的弱绿光发射，对应于 (4)G(7/2)-> I-4(9/2) 跃迁。来自 P-2(1/2) 能级的几个上转换蓝色发射和由于 I-4(9/2)-> P-2(1/2) 跃迁引起的吸收线表明 PbWO4 晶格中 Nd3+ 离子的多位点结构。我们研究了上转换发射的激发光谱及其泵浦功率依赖性和寿命，从中提出并分析了可能的上转换机制。源自D-4(3/2)能级(紫外发射)和P-2(1/2)能级(蓝光发射)的上转换发射的主要机制被证明是连续的双光子激发态吸收，而能量转移上转换过程负责Nd3+的(4)G(7/2)能级的绿色上转换发射。
Upconversion emission properties of Nd3+ ions doped in PbWO4 crystal are investigated by pulsed laser excitation into the (4)G(5/2)+(2)G(1)(7/2) levels at temperatures from 10 to 295 K. The main upconversion emission consists of strong blue emission bands in the wavelength region of 435-447 nm corresponding to the P-2(1/2)-> I-4(9/2) transitions. Some UV bands located in the wavelength region of 356-397 nm corresponding to the D-4(3/2)-> I-4(9/2), I-4(11/2), and I-4(13/2) transitions and weak green emission at 525.2 nm corresponding to the (4)G(7/2)-> I-4(9/2) transition are observed. Several upconversion blue emissions from the P-2(1/2) level and the absoprtion lines due to the I-4(9/2)-> P-2(1/2) transition indicate multisite structure of the Nd3+ ions in the PbWO4 lattices. We investigate the excitation spectra of the upconversion emissions and their pump power dependence and lifetimes from which the probable upconversion mechanisms are proposed and analyzed. The dominant mechanisms for the upconversion emission originating from the D-4(3/2) level (UV emission) and the P-2(1/2) level (blue emission) are proven to be the sequential two-photon excited-state absorption, while the energy transfer upconversion process is responsible for the green upconversion emission from the (4)G(7/2) level of Nd3+.