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采用高温固相反应法合成了YAG: 0.02Cr3+,yYb3+系列粉末材料,研究了该系列材料在近红外区域的发光特性,主要包括Cr3+,Yb3+的发光性质、Cr3+: 4T2和Yb3+: 2F5/2能级辐射跃迁寿命以及其布居时间的比较,给出了Yb3+最佳掺杂量为10%。实验表明:通过Cr3+→Yb3+能量传递,实现了Yb3+在1 000 nm附近近红外发光的增强,这对进一步提高c-Si太阳能电池转换效率打下了坚实基础。 相似文献
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用方波电源驱动808 nm,980 nm激光二极管(LD)激发Er3+掺杂的亚碲酸盐氟氧化物玻璃,测量2H11/2,4S3/2能级上转换发光的上升和衰减,不同波长激发下的上升时间常数不同,说明808 nm LD和980 nm LD激发下2H11/2,4S3/2能级上转换激发途径不同.通过建立速率方程模型分析了4S3/2能级的上升特性与中间能级寿命的关系,从而确定了两种波长激发下上转换绿光的激发机理.
关键词:
上转换
激发过程
3+')" href="#">Er3+
方波激发 相似文献
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根据Er3+-Yb3+共掺碲酸盐玻璃绿光上转换发光的能级结构和相关跃迁建立的速率方程模型,分析了Er3+的4S3/2能级上升特性与4I11/2能级和Yb3+的2F5/2能级的关系.通过模型对实验观测的上升和衰减曲线的拟合,确定速率方程模型的相关参数,计算4S3/2能级粒子数布居趋于稳定时能量传递粒子数与激发态吸收粒子数之比.进一步分析了Er3+-Yb3+共掺绿光上转换发光的动力学过程.
关键词:
速率方程模型
上转换
3+-Yb3+')" href="#">Er3+-Yb3+
方波激发 相似文献
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为提高稀土掺杂TiO2薄膜的上转换效率,采用溶胶-凝胶法和旋涂镀膜工艺制备了Yb3+-Er3+共掺杂SiO2/TiO2上转换光致发光薄膜,研究了SiO2对TiO2薄膜形貌以及发光性能的影响。利用FE-SEM观察了薄膜的表面形貌,利用分光光度计测试了薄膜在近红外光区域的透射率的变化,并用荧光光谱仪测试了薄膜的上转换发光光谱。结果表明:SiO2的掺杂导致TiO2颗粒尺寸显著减小,TiO2薄膜在近红外的透射率也有所下降。在980 nm红外光激发下,SiO2/TiO2薄膜在630~670 nm处获得了明显的上转换红光发射,在516~537 nm和537~570 nm处获得了较弱的上转换绿光发射。由上转换发光强度与激光泵浦功率的关系推知,绿色和红色上转换发光均为双光子吸收发射过程。 相似文献
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在此报告钙铝锗石榴石Ca3Al2Ge3O12中Cr3+离子的光谱特性,依据不同浓度的样品在不同温度下发射光谱的实验结果,分析了不等价Cr3+发光中心零声子线R1,R2的位置变化情况。通过对Cr3+吸收和发射光谱的分析,估算了Cr3+所处格位的晶场强度参数Dq和Racah参数,同时,对低温下Cr3+R线边带振动光谱的精细结构的起因进行了分析和指认。在室温和低温下测得Cr3+的4T2→4A2和2E→4A2能级跃迁的荧光衰减为单指数规律。 相似文献
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Polycrystalline GdAl3(BO3)4 phosphors codoped with Yb3+/Tb3+ and/or Nd3+/Yb3+/Tb3+ have been synthesized by combustion method. Upon excitation with a 980 nm laser diode, an intense green upconversion luminescence
has been observed in GdAl3(BO3)4:Yb,Tb phosphor. The quadratic dependence of the luminescence on the pump-laser power indicating a cooperative energy transfer
process. Meanwhile, it is noticed that upon excitation with 808 nm laser diode, intense luminescence has clearly been detected
in GdAl3(BO3)4:Nd,Yb,Tb phosphor. The luminescence intensity exhibits also a quadratic dependence on incident pump-laser power. However,
no green-emission has been observed in GdAl3(BO3)4 phosphors codoped with Yb3+/Tb3+ or Nd3+/Tb3+ respectively upon excited at 808 nm laser diode. A proposed upconversion mechanism involving energy transfer from Nd3+ to Yb3+, and then a cooperative energy transfer process from two excited Yb3+ to Tb3+ has been presented. 相似文献
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利用皮秒Nd:YAG脉冲激光器作为激发光源,测量出光子能量介于1.36 μm (0.912 eV)—1.80 μm (0.689 eV)之间的硅间接跃迁双光子吸收系数谱.尽管此波段范围内的激光光子能量小于硅间接带隙,但当激光辐照在硅基光电二极管受光面时,在二极管两电极端仍然探测到了显著的脉冲光伏信号.光伏信号峰值强度与入射光强呈二次幂函数关系,表明其是双光子吸收过程.采用pn结等效结电容充放电模型,将光伏响应信号峰值与入射光强相关联,从中提取出硅的间接跃迁双光子吸收系数,改变入射波长得到系数谱.研究表明: 相似文献
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A passively Q-switched 1.06 μm laser with Cr4+:YAG saturable absorber by direct 879 nm diode pumping grown-together composite GdVO4/Nd:GdVO4 crystal to the emitting level was demonstrated in this paper. The characteristics of pulsed laser were investigated by using
two kinds of Cr4+:YAG crystal with the initial transmissivity of 80 and 90%, respectively. When the T
0 = 90% Cr4+:YAG was used, an average output power of 1.59 W was achieved at an incident pump power of 10 W. The pulse width and repetition
rate were 64.5 ns and 170 kHz, respectively. The thermal lens effect of laser crystal was analyzed. 相似文献
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V.V. Ter-Mikirtychev I.T. McKinnie D.M. Warrington Y. Kalisky S.A. Pollack 《Optics & Laser Technology》1997,29(7):407-410
The characteristics of a 940 nm pumped Cr4+:forsterite laser have been investigated using a pulsed colour centre laser as the excitation source. Laser threshold, slope efficiency and temporal behaviour have been determined for high and low Cr4+ doped material. 940 nm pumping is found to be more efficient than 532 and 730–770 nm excitation. Discrepancies with 1064 nm pumping are attributed to excited state absorption. Absorption saturation measurements have been used to assess the potential applications of Cr4+:forsterite, Cr4+:YAG and Cr4+: Lu3A15O12 (LuAG) as passive Q-switches for Nd lasers in the 940 nm region. 相似文献
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V. K. Rai 《Applied physics. B, Lasers and optics》2009,95(2):329-333
Upconversion luminescence in triply ionized praseodymium-doped TeO2–Li2O glass using excitation at ∼590 nm into the 1D2 level from a dye laser pumped with the second harmonic of a pulsed Nd:YAG laser has been reported. The mechanism involved
in the upconversion emission observed at ∼480 nm indicates that the most important contribution is energy transfer among praseodymium
ions in pairs followed by the dipole–dipole interaction. The rate-equation model for the emission at ∼480 nm that provides
direct information to determine the energy-transfer rates containing the pair of states involved in the upconversion process
has been explored. 相似文献
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The temperature dependence of the decay time (τ) of the luminescence pulses from the 440 nm emission band as well as the rise time (τR) of luminescence pulses from the 575 nm emission band has been investigated for KI : In by pulsed light excitation in the A absorption band. From the agreement of τ and τR independent of the temperature it can be concluded that the X minimum on the 3T14 adiabatic potential energy surface (APES) is mainly populated by a radiationless transition from the tetragonal T minimum of the same APES.Furthermore, a comparison of parameters for the impurity centre luminescence corresponding to the tetragonal emission band in KI : In and KI : Tl has been drawn. 相似文献
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F. Chen X. Yu C. Wang R. P. Yan X. D. Li J. Gao Z. H. Zhang J. H. Yu 《Laser Physics》2010,20(6):1275-1278
A diode-end-pumped passively Q-switched 912 nm Nd:GdVO4/Cr:YAG laser is demonstrated for the first time. In a concave-piano cavity, pulsed 912 nm laser performance is investigated
using two kinds of Cr:YAG crystal with different unsaturated transmission (T
U) of 95% and 90% at 912 nm as the saturable absorbers. When the T
U = 90% Cr:YAG is used, as much as 2.6 W average output power for short pulsed 912 nm laser is achieved at an absorbed pump
power of 34.0 W, corresponding to an optical efficiency of 7.6% and a slope efficiency of 20.3%. Moreover, 10.5 ns duration
pulses and up to 2.3 kW peak power is obtained at the repetition rate around 81.6 kHz. 相似文献
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Minoru Itoh 《Journal of luminescence》2012,132(3):645-651
Luminescence properties of CdMoO4 crystals have been investigated in a wide temperature range of T=5–300 K. The luminescence-excitation spectra are examined by using synchrotron radiation as a light source. A broad structureless emission band appears with a maximum at nearly 550 nm when excited with photons in the fundamental absorption region (<350 nm) at T=5 K. This luminescence is ascribed to a radiative transition from the triplet state of a self-trapped exciton (STE) located on a (MoO4)2? complex anion. Time-resolved luminescence spectra are also measured under the excitation with 266 nm light from a Nd:YAG laser. It is confirmed that triplet luminescence consists of three emission bands with different decay times. Such composite nature is explained in terms of a Jahn–Teller splitting of the triplet STE state. The triplet luminescence at 550 nm is found to be greatly polarized in the direction along the crystallographic c axis at low temperatures, but change the degree of polarization from positive to negative at T>180 K. This remarkable polarization is accounted for by introducing further symmetry lowering of tetrahedral (MoO4)2? ions due to a uniaxial crystal field, in addition to the Jahn–Teller distortion. Furthermore, weak luminescence from a singlet state locating above the triplet state is time-resolved just after the pulse excitation, with a polarization parallel to the c axis. The excited sublevels of STEs responsible for CdMoO4 luminescence are assigned on the basis of these experimental results and a group-theoretical consideration. 相似文献
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N. N. Vasil’ev 《Optics and Spectroscopy》2007,102(3):426-431
It is experimentally shown that the Mn2+ ionic subsystem in the three-and two-dimensional structures of diluted magnetic semiconductors of the II–VI groups is saturated upon pulsed excitation by high-power laser radiation with a wavelength of 532.1 nm at temperatures of 77 and 4 K. The direct excitation under these conditions leads to saturation of the inhomogeneously broadened 4 T 1 level of a part of Mn2+ ions, which is confirmed by the estimation of the fraction of excited ions. Processing of the integral kinetic curves of the intracenter luminescence band in the region of 2 eV shows that an increase in the excitation intensity gives rise to a fast component with a decreasing lifetime. Based on the data obtained, it is assumed that, along with the previously studied cooperative effect, redistribution occurs of excitation from localized to delocalized states as a result of more effective saturation of the former. 相似文献
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研究了Er3+离子掺杂钡镓锗玻璃的吸收光谱、拉曼光谱和上转换光谱.分析了Er3+离子在钡镓锗玻璃中的上转换发光机理.结果表明:玻璃的最大声子能量为828cm-1,紫外截止波长为275nm.采用800nm和980nmLD激发玻璃样品,在室温下观察到强烈的上转换绿光和红光发射.随着Er3+离子浓度的增加,绿光发光强度先增加后减小,而红光发光强度呈单调递增趋势.能量分析表明:800nmLD激发产生的绿光主要源于Er3+离子4I13/2能级的激发态吸收过程;红光发射主要源于Er3+离子4I13/2能级与4I11/2能级之间的能量转移过程.980nmLD激发产生的绿光主要源于Er3+离子4I11/2能级之间的能量转移过程;而红光发射主要源于Er3+离子4I13/2能级与4I11/2能级之间的能量转移过程和4I13/2能级的激发态吸收过程.通过量子效率分析,发现采用800nmLD激发Er3+离子掺杂浓度为1mol% 的样品时,上转换绿光发光效率最高.
关键词:
上转换发光机理
3+离子掺杂')" href="#">Er3+离子掺杂
钡镓锗玻璃 相似文献