金属/介质亚波长结构之超分辨特性研究

	金属/介质亚波长结构之超分辨特性研究
	李伶俐
学位类型	博士
导师	鱼卫星
	2014-07
学位授予单位	中国科学院大学
学位专业	光学
摘要	当微细加工技术应需而从微米尺寸迈向纳米尺寸时，在纳米尺度上，材料和结构展现出了新颖的宏观领域无法比拟的特性，打破了许多研究领域的传统限制，迅速激起人们对在纳米尺度控制物质的光电结构及其与光场的相互作用的研究热潮。光学与纳米技术的碰撞一时之间将纳光子学推至研究的前沿，应运而生地，表面等离子体光子学（Plasmonics）从纳光子学研究领域脱颖而出。尤其对基于表面等离子体的亚波长结构的研究，这主要是因为光与亚波长结构的作用表现可通过变化结构等方式予以控制，以期实现研究目标，例如实现衍射极限的超越便打开了超分辨成像应用的大门，除此之外还发展研究了纳米光刻、生物传感、数据存储等应用领域。作为应用之一的基于表面等离子体激元的纳米光刻技术，由于其超衍射极限的光学特性，因而理论上分辨率可以无限小，有望实现光子学、电子学元件在纳米尺度上的完美联合，集成于同一芯片上，从而使其成为下一代纳米制造技术的强有力的备选者之一。然而目前基于表面等离子体激元的纳米光刻技术尚存在纳米光斑对称性差、工作距离难以控制、加工效率低下等问题，难以达到芯片生产所要求的技术和装备标准。为了克服或解决以上技术难点，本研究对表面等离子体激元超聚焦亚波长结构进行了设计，主要做的研究内容有：首先，提出一种同心圆环表面等离子体纳米透镜，为了获得圆形纳米焦斑，采用了径向偏振光照射，利用时域有限差分方法进行数值仿真，发现了表面等离子体透镜的Talbot效应，即在出射面后有5个聚焦区域，且第一个圆形焦斑的强度最强，焦斑半高全宽达到100纳米，并且发现该效应只发生在入射波长小于透镜周期一半时。表面等离子体透镜的Talbot效应的发现，无疑给纳米光刻技术中存在的纳米光斑对称性差和工作距离难以控制难题的解决带来了曙光。其次，为了考察不同偏振光对聚焦特性的影响，又进一步模拟了相似的铝膜结构在线性偏振光照明下的聚焦特性，同样发现了Talbot效应。为了验证表面等离子体纳米透镜的Talbot效应，利用聚焦离子束技术（FIB）加工制作了铝纳米透镜，并利用近场扫描显微镜（NSOM）做了近场光学实验，进而从理论和实验两方面验证了表面等离子体纳米透镜的Talbot效应。随后，设计了一种浸入式纳米透镜，其结构尺寸随着浸入介质和入射波长的改变而改变，利用时域有限差分方法对径向偏振光入射时银纳米透镜浸入四种不同介质情况进行了研究，还对铝、金纳米透镜聚焦效果与入射波长的相关性进行了深入的分析研究，获得了突破衍射极限的圆形纳米焦斑，焦斑尺寸仅为入射波长的四分之一。研究结果不仅给后续研究提供了参考，还对纳米光刻、超分辨成像及数据存储等潜在应用领域具有一定的影响。
其他摘要	The ever-increasing demand for faster information transport and processing capabilities has driven enormous progress in the microfabrication technology. We have witnessed a contiuous progression towards smaller, faster, and more efficient electronic devices since 1950s. The scaling of these devices has also brought about a myriad of challenges associated with electronic interconnection. On the other hand, a candidate technology has recently emerged and has been termed ‘plasmoncis’, which exploits the unique properties of nanoscale metallic structures to route and manipulate light at the nanoscale. Especially for metal-dielectric subwavelength structure, surface plasmon polaritons (SPPs) as a special type of light wave would be excitated and propagate along the metal-dielectric interface. Even the novel optical properties show that plasmonic nanostructure could break the diffraction limit and have bright prospects in super resolution imaing, biosensing, and nanolithography. Furthermore, optical interconnects possess an almost unimaginablely large data carrying capacity. Thereby merging photonics and electronic at nanoscale dimensions can be attained by integrating plasmonic, electric, and conventional photonic devices on the same chip, which should facilitate manufacture. Unfortunately, plasmonic nanolithography technology presents some challenges, such as focal spot being not perfectly symmetrical, space between the direct write array and wafer stage hardly being controled at nanometer accuracy, and low efficiency in the production process. For these problems, we are interesting to propose a metallic subwavelength structure, which was called plasmonic nanolens. In the beginning, the radially polarized light was used in our finite difference time domain (FDTD) numerical simulation for obtaining circular focal spot, and then the Talbot effect of plasmonic nanolens was discovered. The first focal spot is perfectly symmetrical and is 100nm in diameter. And it is found that the Talbto effect can be observed on conditon that the incident wavelength is smaller than half of the period of the nanolens. Subsequently, an Al nanolens was fabricated by focused ion beam (FIB) technology, and by near-field scanning optical microscopy (NSOM) the plasmonic Talbot effect was proved iulluminating by linearly polarized light. Recently, we considered an immersion plasmonic structure. The focusing properties of nanolens being immersed in four medium were studied. Being different from the previous structure, the period of nanolens was supposed to be equal to plasmonic wavelength. Moreover, the influence of metal material and incident wavelength on super focusing properties was researched. Finally, circular focal spot with diameter of a quarter of incident wavelength was obtained, which break through diffraction limit.The super resolution properties of plasmonic nanolens could be expected to apply in various fields including nanolithgraphy, near field microscopy, sensing, and data storage.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/41428
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	李伶俐. 金属/介质亚波长结构之超分辨特性研究[D]. 中国科学院大学,2014.

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