亚带隙光辅助电场极化法致Ge-S玻璃SHG性能微观机制研究

发布时间：2018-06-17 12:25

本文选题：硫系玻璃 + 亚带隙光辅助电场极化法　；参考：《武汉理工大学》2015年硕士论文

【摘要】：近些年来,采用不同极化方法在玻璃材料中诱导二次谐波发生(SHG)性能引起了人们的很大兴趣,并提出了多种理论解释这一现象,但各国研究者对SHG性能产生的微观机制尚未达成共识。本课题基于硫系玻璃材料中光致各向异性在亚带隙光辐照下有最大的光敏特性且能产生光致流动性,采用亚带隙光辅助电场极化法,研究了激光功率、极化电压、材料组分变化以及极化方式对SHG性能的影响规律,采用Raman光谱、透过光谱、原子力显微镜AFM、扫描电镜SEM以及EDS能谱图等现代材料测试方法,探索了玻璃极化区域的热力学过程的演变规律,确定了最佳极化条件,揭示了硫系玻璃SHG性能及其弛豫行为的相关机理。该研究对于分析硫系玻璃材料中SHG性能产生的根源以及探讨氧化物玻璃材料中建立的物理模型是否同样适用于硫系玻璃,并且丰富硫系玻璃的SHG性能理论,具有十分重要的科学研究和实际应用价值,为光电子材料器件诸如光学倍频器,全光开关的开发与设计提供了理论支撑。本文分别选用GeS4、GeS5块体玻璃作为研究对象,主要研究结果如下:1、采用熔融-淬冷技术制备了Ge-S组分的块体玻璃材料,GeS4、GeS5玻璃成玻性能良好;GeS4、GeS5玻璃在基频光1064nm处的透过率分别为78.31%,74.73%,在倍频光532nm处的透过率分别为59.53%,52.80%,满足了实验要求;Raman光谱表明GeS5玻璃中的S8环结构基元各对应峰的强度都要比相应GeS4玻璃的强,为解释材料的组分变化对其SHG性能影响提供了实验依据。2、设计并搭建了亚带隙光辅助电场极化装置,实现了室温下空气介质中简易清洁高效对硫系玻璃材料的极化处理,满足了光电材料的应用要求。3、采用亚带隙光辅助电场极化法,在Ge-S玻璃中获得了SHG性能;极化条件的研究表明:相对SH信号强度随激光功率的增大,先逐渐增强,180mW时得到极大值,随后出现减小的趋势,因此激光功率对相对SH信号强度的影响具有双重作用,与其热效应有关;相对SH信号强度随极化电压的增大,先逐渐增强,3.5kV之后趋于饱和;得到了最佳极化条件(激光功率180mW,极化电压3.5kV,极化时间1h,保压时间1h);极化后样品的SH信号存在弛豫现象,放置两周后,SH信号就较弱了,与玻璃基体中的结构基元从高能激发态自发辐射释放能量的过程有关;采用线极化的极化方式,在玻璃中写入了倍频波导。4、对玻璃极化区域的热力学过程演变规律进行研究,结果表明:Ge-S玻璃极化前后Raman光谱中各结构基元的主峰峰位基本没有改变,只是峰的强度有所增强,归因于材料中结构基元吸收了能量,其热振动变得更加剧烈;透过光谱结果表明材料极化后整体的透过性能有所下降,且向长波段偏移即发生了红移,这与光致暗化现象比较类似,归因于玻璃基体吸收了能量;AFM以及SEM形貌图结果表明极化后区域的平均粗糙度比相应极化前的有所增加,这与亚带隙光辐照后引起的光致流动性体效应有关;EDS能谱图结果表明极化后与极化前相比Ge元素的含量基本不变,S元素的含量有所减少,O元素的含量有所增加,归因于所用的外场比较强,且在空气中做极化,极化区域发生了部分氧化。5、SHG性能的产生缘于亚带隙光辅助电场极化破坏了玻璃的各向同性,产生了倍频信号;采用偶极子取向模型解释机理;利用经典Tauc方程计算样品的允许直接跃迁光学^/隙(Eoptd)、允许间接跃迁光学^/隙(Eopti)以及Urbach能量(?E)。结果表明GeS5玻璃的光学^/隙值比GeS4玻璃的小,它的电子跃迁容易,因而其非线性效应增强;另外GeS5玻璃的Urbach能量值比GeS4玻璃的大,它的带破裂与缺陷形成的趋势就越大,由此也能说明GeS5玻璃比GeS4玻璃更易于被极化,极化后表现出更强的倍频功能。
[Abstract]:In recent years, the use of different polarization methods to induce the two harmonic generation (SHG) in glass materials has aroused great interest, and a variety of theoretical explanations have been put forward, but the researchers of various countries have not reached consensus on the micro mechanism of the performance of SHG. The gap light has the greatest photosensitivity and can produce photoinduced fluidity. Using the sub band gap light assisted electric field polarization method, the influence of laser power, polarization voltage, material component change and polarization mode on SHG performance is studied. Raman spectrum, transmission spectrum, primary subforce microscope AFM, scanning electron microscope SEM and EDS energy spectrum are used. On behalf of material testing method, the evolution law of thermodynamic process of glass polarization region was explored, the optimum polarization condition was determined, and the related mechanism of SHG properties and relaxation behavior of sulphur system glass was revealed. The research on the origin of SHG properties in sulphur glass materials and the physical model established in oxide glass materials were discussed. Whether it is suitable for sulphur based glass and enriching the SHG property theory of sulfur based glass has very important scientific research and practical application value. It provides theoretical support for the development and design of optoelectronic material devices such as optical frequency doubler and all optical switch. This paper selected GeS4 and GeS5 bulk glass as the research object. The results are as follows: 1, the bulk glass materials of Ge-S components are prepared by the melt quenching technology, and the properties of GeS4 and GeS5 glass are good, and the transmittance of GeS4, GeS5 glass at the basic frequency 1064nm is respectively 74.73%, and the transmittance of the 532nm at the frequency doubling light is 59.53% and 52.80%, respectively. The Raman spectrum shows the GeS5 glass in the GeS5 glass. The strength of each corresponding peak of the S8 ring structure is stronger than that of the corresponding GeS4 glass. It provides an experimental basis for explaining the influence of the composition of the material on its SHG performance. The sub band gap optical auxiliary electric field polarization device is designed and built, which realizes the simple cleaning and high efficiency of the polarization treatment of the sulphur glass material in the air medium at room temperature. The application of optoelectronic materials requires.3, using the sub band gap light assisted electric field polarization method to obtain the SHG performance in the Ge-S glass. The polarization condition study shows that the relative SH signal strength increases gradually with the increase of laser power, and the maximum value is obtained at 180mW, then the trend is reduced. Therefore, the effect of laser power on the relative SH signal intensity is presented. The relative SH signal strength increases with the increase of the polarization voltage and then becomes saturated with the increase of the polarization voltage. The optimum polarization conditions are obtained (laser power 180mW, polarization voltage 3.5kV, polarization time 1H, holding time 1H), and the relaxation phenomenon of SH signal after polarization, and SH signal is weaker after two weeks of polarization. The structural elements in the glass matrix are related to the spontaneous emission of energy from the spontaneous emission of high energy excited states. The linear polarization polarization mode is used to write the frequency doubling waveguide.4 in the glass. The thermodynamic process evolution of the polarized glass region is studied. The results show that the main peak peak of each structural element in the Raman spectrum of the Ge-S glass before and after the polarization of glass is the peak peak. The strength of the peak is not changed, but the strength of the peak is enhanced, which is attributed to the absorption of energy in the structural elements in the material, and its thermal vibration becomes more intense. The transmission properties of the whole material after the polarization of the material decrease, and the red shift occurs to the long band, which is similar to the photoluminescent phenomenon, which is attributed to the glass base. The body absorbs energy; the results of AFM and SEM morphologies show that the average roughness of the polarized region is higher than that before the polarization, which is related to the photoinduced fluidity effect after the subband Gap light irradiation. The EDS energy spectrum shows that the content of the Ge element is basically the same as before polarization, and the content of the S element is reduced, O The content of the element is increased, which is attributed to the strong external field and polarization in the air and the partial oxidation of.5 in the polarized region. The performance of the SHG is caused by the subband Gap light assisted electric field polarization destroying the isotropy of the glass, producing the frequency doubling signal, using the dipole orientation model to explain the mechanism, and using the classical Tauc equation to calculate the mechanism. The sample allows the direct transition of optical / optical / gap (Eoptd) to allow the indirect transition optical / / / Eopti and Urbach energy (? E). The results show that the optical / optical / gap value of the GeS5 glass is smaller than that of the GeS4 glass, and its electronic transition is easy and its nonlinear effect is enhanced; and the Urbach energy value of the GeS5 glass is larger than that of the GeS4 glass, and its band rupture and defects are broken. The greater the trend is, the GeS5 glass is easier to polarize than GeS4 glass, and shows stronger frequency doubling after polarization.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ171.1

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