硅纳米线太赫兹波调控技术

发布时间：2018-04-25 02:20

本文选题：太赫兹波 + 硅纳米线　；参考：《电子科技大学》2017年硕士论文

【摘要】：太赫兹辐射(T-rays)逐渐成为高科技领域中的研究热点,与其相关的产生、发射、接收、探测以及调控设备都有了很大进步,T-rays已经成为人类对物质世界进行认知的一项有利工具。对T-rays调控技术的研究是使用这项工具的基础和前提。太赫兹(THz)频段在紫外光之下,其光子能量为1-100meV,不足以使物质发生电离,因此T-rays具有非电离、非破坏特性。这些特点使得T-rays技术得到了快速发展和广泛应用,从生化光谱学、天文学和纳米材料科学等基础科学,到环境科学、医疗卫生、农业和安全等应用领域。其中,THz成像是T-rays技术最具潜力和最具商业价值的应用领域。在THz成像系统中,空间太赫兹波调制器在很大程度上影响着成像质量和成像速率,但相关制作材料的缺乏是影响其性能的关键因素。本文将目光投向了在可见光波段具有良好减反性能的硅纳米线(SiNW),研究其与T-rays的相互作用,以及在激光作用下对T-rays的调控能力。首先运用THz时域光谱测试平台测试了高阻硅片(HR-Si)及不同长度SiNW的时域谱,证明了SiNW对T-rays有增透作用,而且增透作用与SiNW的长度成正比。结合时域谱所对应的频域谱及透射率变化情况,得出了915nm激光作用下,2.5μm SiNW的调制效果最佳;808nm激光作用下,1μm SiNW的调制效果最佳,900mW下THz波的透射率从不加激光时的70%下降到10%以下。其次,在连续THz波谱测试平台上测试了HR-Si及不同长度SiNW在0.34THz下的THz波透射谱,915nm激光时,900mW下最大调制深度MD5μm=38.8%;808nm激光作用下,900mW时最大调制深度MD2.5μm=53.7%,相同激光功率作用下,808nm激光的调制作用更明显。通过对调制深度与SiNW长度关系的分析,认为不同长度SiNW上光生载流子的分布位置是其非线性关系的决定因素。最后,对SiNW建立起了单层与九层膜系,发现九层膜系按照传输矩阵理论计算出来的反射率与实验结果更加吻合。
[Abstract]:Terahertz radiation T-rays (T-rays) has gradually become a research hotspot in the field of high technology, and its related production, emission, reception, detection and control equipment have made great progress. T-rays have become a favorable tool for human cognition of the material world. The research of T-rays control technology is the foundation and premise of using this tool. Terahertz (THz) band is under ultraviolet light, and its photon energy is 1-100meV, which is not enough to ionize the matter. Therefore, T-rays has the characteristics of non-ionization and non-destruction. These characteristics have led to the rapid development and wide application of T-rays technology, ranging from basic sciences such as biochemical spectroscopy, astronomy and nanomaterials science to environmental science, health care, agriculture and safety. THz imaging is one of the most promising and commercial applications of T-rays technology. In THz imaging system, space terahertz wave modulator greatly affects the imaging quality and imaging rate, but the lack of related materials is the key factor to affect its performance. In this paper, we focus on Si nanowires with good anti-reflection performance in the visible light band, and study their interaction with T-rays and their ability to regulate T-rays under laser action. The time domain spectra of HR-Si) and SiNW of different lengths were measured by THz time-domain spectroscopy. It is proved that SiNW has antireflective effect on T-rays, and the antireflection effect is proportional to the length of SiNW. According to the frequency domain spectrum and the transmissivity change of time domain spectrum, the optimal modulation effect of 2.5 渭 m SiNW under the action of 915nm laser is obtained. The best modulation effect of 1 渭 m SiNW under the action of 915nm laser is obtained. The transmittance of THz wave decreases from 70% to less than 10% when the laser is not added. Secondly, The maximum modulation depth (MD5 渭 m) of HR-Si and SiNW with different lengths under 0.34THz 915nm laser at 915mW was measured on a continuous THz spectrum test platform. The maximum modulation depth at 808nm laser was 38.8nm and the maximum modulation depth of MD2.5 渭 mW was 53.7nm. The maximum modulation depth of 808nm laser under the same laser power was measured. The modulation effect is more obvious. Based on the analysis of the relationship between modulation depth and SiNW length, it is considered that the distribution of photogenerated carriers on SiNW with different lengths is the decisive factor of its nonlinear relationship. Finally, the monolayer and nine-layer systems are established for SiNW, and it is found that the reflectivity calculated by the nine-layer system according to the transfer matrix theory is in better agreement with the experimental results.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.2;TB383.1

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