Optical planar waveguides in Yb³⁺-doped phosphate glasses produced by He⁺ ion implantation

Optical planar waveguides in Yb 3+-doped phosphate glasses are fabricated by implanting triple-energy helium ions. The guiding modes and the near-field intensity distribution are measured by using the prism-coupling method and the end-face coupling setup with a He-Ne laser at 633 nm The intensity calculation method (ICM) is used to reconstruct the refractive index profile of the waveguide. The absorption and the fluorescence investigations reveal that the glass bulk features are well preserved in the active volumes of the waveguides, suggesting the fabricated structures for possible applications as waveguide lasers.     

Optical transitions in Er^3＋ doped lead germanate glasses

Er^{3+}- and Er^{3+}/Yb^{3+}-doped lead germanate glasses that are suitable for use in fibre lasers and optical amplifiers as well as optical waveguide devices have been fabricated and characterized. The absorption spectra from near-infrared to visible were obtained and the Judd－Ofelt parameters were determined from the absorption band. Intense and broad 1.53μm infrared fluorescence and visible upconversion luminescence were observed under 976 nm diode laser excitation. For 1.53μm emission band, the full widths at half-maximum are 36, 37, 51 nm for GPE, GPYE and GPFE samples, respectively. For frequency upconversion emission, the intense bands centred at around 524, 545, 657nm are due to the {}^4S_{3/2}+{}^2H_{11/2}→{}^4I_{15/2} and {}^4F_{9/2}→{}^4I_{15/2} transitions of Er^{3+} ions. The quadratic dependence of the green and red emissions on excitation power indicates that the two-photon absorption process occurs under the 976nm excitation.     

Optical parameters of Nd3＋：Er3＋：yb3＋ co-doped borosilicate glasses and their energy transfers at high temperature

This paper reports that a series of Nd³⁺:Er³⁺:Yb³⁺ co-doped borosilicate glasses have been prepared and their absorption spectra measured. The J--O intensity parameters Ω_k (k=2, 4, 6), spontaneous radiative lifetime τ_rad, spontaneous transition probability A, fluorescence branching ratio β and oscillator strength f_ed of the Nd³⁺ ions at room temperature are calculated based on Judd--Ofelt (J--O) theory. The temperature dependence of the up-conversion photoluminescence characteristics in a Nd³⁺:Er³⁺:Yb³⁺ co-doped sample is studied under a 978 nm semiconductor laser excitation, and the energy transfer mechanisms among Yb³⁺, Er³⁺ and Nd³⁺ ions are analysed. The results show that the J--O intensity parameters Ω₂ increase when the Nd³⁺ concentration of the Nd³⁺:Er³⁺:Yb³⁺ co-doped borosilicate glasses increases. The possibility of spontaneous transition is small and lifetimes are long at levels of ⁴F_5/2 and ⁴F_3/2. The intensity of Nd³⁺ emissions at 595, 691, 753, 813 and 887 nm are markedly enhanced when the sample temperature exceeds 400 K. The reasons being the cooperation of the secondary sensitization from Er³⁺ to Nd³⁺ and the contribution of a multi-phonon.     

Optical properties of phosphate glasses co-doped with Yb~（3＋） and silver nanoparticles

We report the fabrication and spectroscopic characterization of Yb^3＋-doped phosphate glass, also containing silver nitrate. Scanning electron microscopy（SEM） provides the evidence of the formation of silver nano-particles（SNPs）, which are formed as a consequence of melting and thermal decomposition of Ag NO3. Absorption spectra of the samples in the visible-to-near-infrared spectral range reveal the presence of bands centered at 410 nm associated with the SNP-plasmon resonance, and at 976 nm due to the Yb^3＋. Under 916-nm laser-diode pumping, the effect of the SNP reflects that： i） the fluorescence in the 950-nm–1150-nm spectral range is strongly enhanced（～ 30 times）, while the fluorescence decay time associated with the ^2F5/2→^2F7/2transition of Yb^3＋ increases 25%, and ii） the basic lasing properties（saturation pumping intensity, the emission and absorption cross sections） are substantially improved.     

Enhanced NIR emission in Ce^3＋/Er^3＋-doped YAG induced by Bi^3＋ doping

Ce^3＋/Er^3＋/Bi^3＋ triply-doped yttrium aluminum garnet （YAG） is synthesized using co-precipitation method. The Bi^3＋ concentration-dependent near-infrared （NIR） emission behavior is systemically in- vestigated. The NIR emission of Er^3＋ ions at 1531 nm is enhanced threefold by the addition of 7 mol% Bi^3＋. Bi^3＋doping results in the formation of exciton in YAG and the variation in the local environment of the doped rare-earth ions. The enhancement in NIR luminescence is ascribed to the combined effects of the sensitization of exciton→Ce^3＋ →Er^3＋ and the Bi^3＋ doping-induced adjustment of the local environment for Ce^3＋ and Er^3＋ ions.     

Photorefractive properties of optical waveguides in Fe:LiNbO<Subscript>3</Subscript> crystals produced by O<Superscript>3+</Superscript> ion implantation

The photorefractive properties of optical planar waveguides in Fe:LiNbO₃ crystals fabricated by O³⁺ ion implantation are investigated. Two-wave mixing experiments are carried out for both the waveguide and the bulk. The results show that the measured gain coefficients are almost identical for the waveguiding layer and the substrate. In the waveguide, the response time could be reduced by one order of magnitude, with respect to the bulk, at the same power level of the incident light.     

Efficient 2.7-μm emission in Er3＋-doped bismuth germanate glass pumped by 980-nm laser diode

An Er 3+-doped lead-free bismuth germanate glass is synthesized. Its 2.7-μm emission property is analyzed, and the efficient 2.7-μm emission from the glass is observed under 980-nm laser diode excitation. The prepared glass possesses high spontaneous transition probability (64.8 s 1 ) and a large calculated emission cross section (6.61×10 21 cm 2 ) corresponding to the 4I11/2→4I13/2 transition. The multiphonon relaxation rate for the excited state 4I11/2 is only 236 s 1 . Therefore, the excellent spectroscopic properties and outstanding thermal stability suggest that this glass is a suitable host for developing solid-state lasers operating in the mid-infrared.     

Annealing effect on planar waveguides in LiNbO3 produced by oxygen ion implantation

We reported on planar waveguides in stoichiometric lithium niobate fabricated by 4.5 MeV oxygen ion implantation with a dose of 6 × 10¹⁴ ions/cm² at room temperature. After ion implantation, these samples were annealed at 240 °C, 260 °C, and 300 °C for 30 min. We investigated annealing effect on the guiding modes and near-field images in the waveguides by prism-coupling method and end-face coupling method respectively. We found that for the extraordinary refractive index a positive alternation occurred in the near-surface region while a negative alternation happened at the end of ion track. Moreover, we measured the transmission spectra for the pure sample and implanted samples before and after annealed at different temperatures, and we observed an absorption peak at ∼480 nm (2.6 eV) in all of these SLN samples.     

Ce3+对Er3+/Yb3+共掺TeO2-WO3-ZnO玻璃发光性能的影响

在Er³⁺/Yb³⁺共掺TeO₂-WO₃-ZnO玻璃中引入Ce³⁺，研究了Ce³⁺对Er³⁺1.5μm发射性能及其上转换发光性能的影响。结果表明，随Ce³⁺浓度的增加Er³⁺1.5μm波段的荧光强度先增强后降低，优化的Ce³⁺掺杂浓度在2.07×10²⁰/cm³左右；1.5μm波段的荧光寿命则随Ce³⁺浓度的增加有轻微降低，从3.4ms降到3.0ms，但Ce³⁺浓度的增加对1.5μm波段的荧光半高宽基本无影响；Er³⁺/Ce³⁺间的交叉弛豫Er³⁺(⁴I_11/2)+Ce³⁺(²F_5/2)→Er³⁺(⁴I_13/2)+Ce³⁺(²F_7/2)使玻璃的上转换发光强度大大降低，但在过高的Ce³⁺浓度下，Er³⁺/Ce³⁺间的另一交叉弛豫Er³⁺(⁴I_13/2)+Ce³⁺(²F_5/2)→Er³⁺(⁴I_15/2)+Ce³⁺(²F_7/2)则使Er³⁺⁴I_13/2能级粒子数减少，导致1.5μm波段荧光强度和荧光寿命降低. 关键词： 碲钨酸盐玻璃 发光性能 3+离子')" href="#">Er³⁺离子 3+离子')" href="#">Ce³⁺离子 交叉弛豫     

N+离子注入聚四氟乙烯表面改性研究

在剂量为1×1014—1×1017ions／cm2的范围内，在不同的温度条件下，用 能量为160keV氮离子对PTFE表面进行注入处理，处理后的样品用可见(514．5nm)和傅里叶红 外(1064nm)拉曼(Raman)光谱以及扫描电镜和x射线能谱仪进行检测.实验结果表明低剂量注 入可以增强PTFE晶体结构的取向和有序性；中等剂量时溅射损失效应明显，表面粗糙度加大 ：高剂量注入时微观结构强烈地变化并生成CC双键，导致表面碳化.另外温度对表面改性效 果有很大的影响.刻蚀率和表面的微观结构的变化随着温度的升高而增强.离子注入前，用喷 射技术使样品覆盖一层150nm的金膜，薄膜的黏结性和硬度用划痕和透明胶带测试配合扫描 电镜进行分析.分析结果表明，黏结性在注入剂量为1014ions／cm2时明显增强，这 个结果与表面亲水性测量结果是一致的.但表面硬度只在温度为180℃时才得到了增强. 关键词： 离子注入 聚四氟乙烯 表面改性     

Cr3+,Yb3+,Er3+共掺磷酸盐铒玻璃转镜调Q激光性质研究

研究了Cr³⁺,Yb³⁺,Er³⁺共掺磷酸盐铒玻 璃转镜调Q激光性质.三种Er₂O₃掺杂浓度的激光实验结果表明，在Er₂O₃名义掺杂浓 度为0.5wt％时，玻璃的综合激 光性质最好，重复频率为0.1Hz时，它的激光阈值功率为14.5mJ，最大输出能量为9.6mJ ，斜率效率为0.55％.在同种实验条件下，比较了Cr14和Kigre公司生产的QE-7S激光性质参数，实验表明，前者激光阈值功率稍低，而后者的斜率效率和最大输出功率略高. 关键词： 3+-Yb³⁺-Er³⁺共掺')" href="#">Cr³⁺-Yb³⁺-Er³⁺共掺 磷酸 盐玻璃 光谱性质 激光性质     

Planar waveguides in neodymium-doped calcium niobium gallium garnet crystals produced by proton implantation

In this work, the fabrication and optical properties of a planar waveguide in a neodymium-doped calcium niobium gallium garnet(Nd:CNGG) crystal are reported. The waveguide is produced by proton(H~+) implantation at 480 ke V and a fluence of 1.0×10~(17) ions/cm~2. The prism-coupling measurement is performed to obtain the dark mode of the waveguide at a wavelength of 632.8nm. The reflectivity calculation method(RCM) is used to reconstruct the refractive index profile. The finite-difference beam propagation method(FD-BPM) is employed to calculate the guided mode profile of the waveguide.The stopping and range of ions in matter 2010(SRIM 2010) code is used to simulate the damage profile induced by the ion implantation. The experimental and theoretical results indicate that the waveguide can confine the light propagation.     

Yb3+敏化的Er3+/Ho3+共掺碲酸盐玻璃的上转换发光研究

用高温熔融法制备了系列Er³⁺/Yb³⁺共掺，Ho³⁺/Yb³⁺共掺，和Er³⁺/Yb³⁺/Ho³⁺三掺碲酸盐玻璃，在975nm激光抽运下三种掺杂玻璃中都出现了较强的绿光和红光上转换.研究了Yb³⁺离子对Er³⁺和Ho³⁺离子上转换发光强度的影响以及Yb³⁺→Er关键词： 3+/Yb³⁺/Ho³⁺共掺')" href="#">Er³⁺/Yb³⁺/Ho³⁺共掺 碲酸盐玻璃 光谱性质 上转换     

He,Au离子辐照AuCu_3致元素表面偏析

采用磁控溅射方法在单晶硅(111)衬底上制备了AuCu_3薄膜,用2 MeV He离子和1 MeV Au离子对薄膜进行辐照,用卢瑟福背散射对He,Au离子辐照前后AuCu_3薄膜近表面的成分变化进行了分析,对不同离子辐照导致的表面元素偏析行为进行了研究.结果表明:当2 MeV He离子辐照时,随着辐照剂量增大,观察到样品近表面Au元素偏析的趋势;当1 MeV Au离子辐照时,随着辐照剂量增大,观察到样品近表面Cu元素偏析的趋势,与He离子辐照相反.通过对He,Au离子在样品中产生的靶原子空位及其分布分析,发现靶原子空位浓度分布的梯度是导致两种不同表面元素偏析趋势的原因,空位扩散是其中的主要机理.     

掺Yb3+双包层大模场面积光纤锁模激光器

报道了一种结构简单、运转稳定并可以输出高脉冲能量的被动锁模光纤激光器.激光器的增益介质为掺Yb³⁺双包层大模场面积光纤,具有非常低的非线性系数.利用非线性偏振旋转效应和半导体可饱和吸收镜结合实现自启动锁模,获得了平均功率为160mW、重复频率为55.9MHz(对应于3nJ的单脉冲能量)、脉冲宽度为10.6ps的激光脉冲输出. 关键词： 大模场面积光纤 光纤激光器 锁模