基于纳米光子结构的光学器件设计与光传输特性的研究

发布时间：2018-03-10 10:33

本文选题：生物传感器　切入点：偏振分束器　出处：《南京理工大学》2016年博士论文　论文类型：学位论文

【摘要】：光子学是一门以光子为主要信息载体的学科。随着人类社会进入21世纪,科学技术飞速发展,光学信息技术在各个领域中都具有非常重要的地位。基于传统光学原理的光子学技术,由于受到衍射极限的限制,很难在纳米尺度层面上有突破性的发展。因此,突破传统光学的一个重要的新概念——纳米光子学作为光子学科的分支应运而生。本论文主要研究了孤立的与周期性的纳米光子结构的光传输特性,并设计了几种纳米光学器件,讨论了其在生物传感与纳米光学集成方面的应用。具体研究内容如下:(1)提出了一种基于光栅结构的表面等离子体共振生物传感器。采用时域有限差分法,讨论了金、银和铝材料,对传感器响应信号的影响。数值分析表明,基于铝材料的传感器具有更好的传感特性,设计所得传感器灵敏度值为247.2 °/RIU,相比于传统光栅型传感器提高了 150%。(2)提出了一种基于双层介质光栅结构的偏振分束器。采用严格耦合波分析法,讨论了该偏振分束器的工作波长与角度带宽。数值分析表明,当入射角在48°到72°,入射波长在1.5μm到1.6μm范围内,分束后得到的TE与TM波的衍射效率均能大于90%。解决了传统光栅型偏振分束器需要固定单一入射波长或入射角度的缺陷。(3)基于高对比度光栅结构对正入射表面的宽频光能产生非常强反射率的特点,设计了一种聚焦反射器。采用时域有限差分法,讨论了不同偏振入射光的聚焦现象。数值分析表明,随着入射波长从1.55μ 变化到2 μm,该器件对TE和TM偏振光均能产生聚焦现象,具有偏振无关性。(4)结合金属纳米球回路理论和传输线理论,提出了一套计算共振金属纳米棒反射相位的分析理论。通过与基于时域有限差分法的复合数值计算结果相比较,该分析理论在纳米棒直径小于70 nm时有很好的准确性。随着纳米棒直径的增加,准静态近似不再适用,此时分析理论结果开始偏离复合数值计算结果,变的不再准确。(5)研究了可见光范围内的单狭缝透射抑制现象。通过公式推导,仿真模拟和实验检测,证明了在TM偏振光入射条件下,随着狭缝的宽度从20 nm变化到70 nm,透射谱在波长约为510nm处均存在光透射抑制现象。(6)研究了金膜上不同开口宽度的纳米双孔结构的三次谐波产生。实验检测与基于三维时域有限差分法的仿真计算同时表明,纳米双孔结构的三次谐波产生信号峰值会随着双孔结构开口宽度的变小而增大。
[Abstract]:Photonics is a subject in which photons are the main carrier of information. With the development of science and technology in 21th century, Optical information technology plays a very important role in all fields. Photonics based on traditional optical principle is difficult to make a breakthrough in nanometer scale because of the limitation of diffraction limit. Nanometer photonics, an important new concept of traditional optics, came into being as a branch of photonics. In this paper, the optical propagation characteristics of isolated and periodic nano-photonic structures are studied, and several kinds of nano-optical devices are designed. In this paper, its application in the integration of biosensor and nano-optics is discussed. (1) A surface plasmon resonance biosensor based on grating structure is proposed. Gold is discussed by using finite-difference time-domain (FDTD) method. The effect of silver and aluminum on the sensor response signal. Numerical analysis shows that the sensor based on aluminum material has better sensing characteristics. The sensitivity of the sensor designed is 247.2 掳/ r RIU.Compared with the traditional grating sensor, a polarization beam splitter based on double-layer dielectric grating structure is proposed. The working wavelength and angular bandwidth of the polarization splitter are discussed. Numerical analysis shows that when the incident angle is between 48 掳and 72 掳, the incident wavelength is in the range of 1.5 渭 m to 1.6 渭 m. The diffraction efficiency of te and TM waves obtained by beam splitting can be higher than 90. The defect of traditional grating polarization beam splitter, which needs to fix single incident wavelength or incidence angle, is solved. The width of normal incident surface based on high contrast grating structure is solved. The characteristic that frequency light energy produces very strong reflectivity, A focusing reflector is designed. The focusing phenomenon of different polarization incident light is discussed by using finite-difference time-domain method. Numerical analysis shows that the focusing phenomenon of te and TM polarized light can be produced by the device with incident wavelength varying from 1.55 渭 to 2 渭 m. Combining with the theory of metal nanospheres loop and transmission line theory, a set of analytical theories for calculating the reflection phase of resonant metal nanorods are proposed. The results are compared with the composite numerical results based on finite-difference time-domain method (FDTD). The analytical theory is accurate when the diameter of nanorods is less than 70 nm. With the increase of the diameter of nanorods, the quasi-static approximation is no longer applicable. The phenomenon of single slit transmission suppression in the visible light range is studied. Through formula derivation, simulation and experimental detection, it is proved that under the condition of TM polarized light incidence, With the width of the slit varying from 20 nm to 70 nm, the optical transmission suppression was observed at the wavelength of about 510 nm.) the third harmonic generation of nanocrystalline double pore structures with different opening widths on the gold film was investigated. The simulation results of 3D finite-difference time-domain method also show that, The peak value of the signal generated by the third harmonic wave will increase with the decrease of the opening width of the double pore nanostructure.
【学位授予单位】：南京理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TP212;TN256

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