用于有机光波导放大器的稀土掺杂氟化物纳米晶研究

发布时间：2018-04-02 16:09

  本文选题：纳米晶　切入点：上转换发光　出处：《吉林大学》2016年博士论文

【摘要】：有机聚合物光波导放大器具有制作工艺简单、制作成本低、折射率容易调整、机械性能好、容易与硅基平面集成等优点,在短距离光通讯系统和光子集成化方面展现出巨大的应用潜力。目前,以稀土配合物为增益介质制作的有机光波导放大器,在相应的光波段已经获得了净增益。但稀土配合物的光漂白性会使器件的稳定性变差。稀土掺杂氟化物纳米晶具有出色的光稳定性、长的荧光寿命、可选择近红外光泵浦等特点,能够克服上述材料的缺陷,成为理想的增益介质。此外,我们可以通过改变掺杂稀土离子的种类制备出适用于不同波段的光波导放大器,例如:近红外光有机光波导放大器(1.5mm波段)、可见光有机光波导放大器(0.6mm波段)。稀土掺杂氟化物纳米晶的分散性、尺寸、发光强度都会影响有机光波导放大器的增益。纳米晶的分散性越好、尺寸越小、发光强度越高,越有利于获得高的增益。目前用于有机光波导放大器的稀土掺杂氟化物纳米晶在分散性、尺寸、发光强度方面存在很多问题。因此,合成分散性好、尺寸小、发光强的稀土掺杂氟化物纳米晶是目前迫切需要解决的问题。本文对用于有机光波导放大器的稀土掺杂氟化物纳米晶进行了系统的研究,取得了以下研究结果:1、为了制备用于近红外有机光波导放大器的分散性好、尺寸小、发光强的稀土掺杂氟化物纳米晶,我们提出了通过层层包覆有源壳层(壳层中包含Yb~(3+)离子)的方法提高小尺寸氟化物纳米晶的发光强度。利用该方法合成了BaLuF_5:Yb~(3+),Er~(3+)@(X-shell,X=1~5)BaLuF_5:Yb~(3+)纳米晶。在976 nm激光的激发下,测试了上述纳米晶的上转换和下转换发光光谱。与Ba LuF_5:Yb~(3+),Er~(3+)核纳米晶相比,BaLuF_5:Yb~(3+),Er~(3+)@(5-shell)Ba Lu F_5:Yb~(3+)核壳纳米晶的上转换和下转换发光强度分别增强52倍和9.8倍;与壳层厚度相同的BaLuF_5:Yb,Er@BaLu F_5:Yb纳米晶相比,BaLuF_5:Yb~(3+),Er~(3+)@(5-shell)Ba Lu F_5:Yb~(3+)纳米晶的上转换(545 nm波长附近)和下转换(1530 nm波长附近)发光强度分别提高了1.3倍和1.1倍。发光强度增强的原因是:包覆有源壳层不仅能够抑制纳米晶的表面猝灭效应;有源壳层中的Yb~(3+)离子还能够吸收泵浦光,并将能量传递给核中激活离子(Er~(3+)II离子),提高泵浦光的利用率;利用层层包覆的方法还能够更好地抑制纳米晶的表面猝灭效应。我们将合成的分散性好、小尺寸、发光强的BaLu F_5:Yb~(3+),Er~(3+)@(5-shell)BaLu F_5:Yb~(3+)纳米晶分散在SU-8聚合物中,制作了有机光波导放大器,在1530 nm波长处获得3.13 dB的相对增益。2、目前,还未见有关基于稀土掺杂氟化物纳米晶的红光有机光波导放大器的相关报道。我们制作出了基于上转换纳米晶的红光有机光波导放大器,实现了对波长为650 nm的光信号的放大。我们通过溶剂热法合成了纯红色上转换发光的KMnF_3:Yb~(3+),Er~(3+)纳米晶。在976 nm激光泵浦下,KMnF_3:Yb~(3+),Er~(3+)纳米晶能够发射出单一的红色上转换发光(来自Er~(3+)离子辐射跃迁:4F9/2→4I15/2),这主要是由于Er~(3+)离子和Mn2+离子之间的能量传递:2H11/2,4S3/2+6A1→4I15/2+4T1,2H9/2+6A1→4I13/2+4T1,4I15/2+4T1→4F9/2+6A1所致。接下来,在KMnF_3:Yb~(3+),Er~(3+)纳米晶表面包覆一层有源壳层合成了具有纯红色上转换发光的KMnF_3:Yb~(3+),Er~(3+)@KMnF_3:Yb~(3+)核壳纳米晶,并将其分散于聚甲基丙烯酸甲酯(PMMA)聚合物中制作了有机光波导放大器,首次实现了对波长为650 nm光信号的放大,获得了3.5 dB的相对增益。3、为了制作宽带近红外有机光波导放大器,稀土掺杂氟化物纳米晶需要具有好的分散性、高的发光强度、宽带的近红外发光的性质。我们通过溶剂热法合成了分散性好并具有宽带近红外发光的KMnF_3:Yb~(3+),Er~(3+)纳米晶。在976 nm激光的泵浦下,KMnF_3:Yb~(3+),Er~(3+)纳米晶在1.5mm波长附近有两个发光峰,其下转换发光光谱的半高全宽(FWHM)比NaYF4:Yb~(3+),Er~(3+)纳米晶的宽14 nm。我们通过包覆有源壳层的方法进一步提高了KMnF_3:Yb~(3+),Er~(3+)纳米晶在1.5mm波长附近的下转换发光,合成了分散性好、发光强、具有宽带下转换发光的KMnF_3:Yb~(3+),Er~(3+)@KMnF_3:Yb~(3+)纳米晶,并将其分散在PMMA聚合物中制作了有机光波导放大器,在1534 nm波长处获得了0.6 dB的相对增益。
[Abstract]:Organic polymer optical waveguide amplifier has the advantages of simple preparation process, low production cost, easy to adjust the refractive index, good mechanical properties, has the advantages of easy and silicon planar integration, showing great potential for application in short distance optical communication and photonic integration. At present, the complexes of rare earth organic waveguide amplifier gain medium production the light in the corresponding band has received a net gain. But the rare earth complexes of light bleaching will make the device stability worse. Rare earth doped fluoride nanocrystals with excellent light stability, long fluorescence lifetime, can choose the near-infrared pump characteristics, can overcome the defects of the material, become the ideal gain medium. In addition, we can change the type of doped rare earth ions were prepared for optical waveguide amplifiers, different bands for example: near infrared organic waveguide amplifier (1.5m M band), visible light organic optical waveguide amplifiers (0.6mm band). The dispersion of rare earth doped fluoride nanocrystal size, the luminous intensity will affect the organic waveguide amplifier. The gain dispersion of nano crystal is smaller, the luminous intensity is high, the more conducive to obtain high gain. For now rare earth doped fluoride nanocrystals Organic Waveguide Amplifier in the dispersion, size, there are many problems in the luminescence intensity. Therefore, the synthesis of good dispersion, small size, rare earth doped fluoride nanocrystals emitting strong is an urgent need to solve the problem. This paper presents a systematic research on rare earth doped fluoride nanocrystals for organic light waveguide amplifier, and obtains the following results: 1, in order to prepare for the near infrared organic waveguide amplifier has good dispersion, small size, strong luminescence of rare earth doped fluoride nanocrystals, we 鎻愬嚭浜嗛，

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