基于超振荡光场的远场超分辨成像原理和方法研究

发布时间：2018-02-15 07:39

本文关键词： 衍射极限超振荡光场超分辨成像宽带消轴向色差　出处：《中国科学院研究生院(光电技术研究所)》2016年博士论文　论文类型：学位论文

【摘要】：成像技术发展是推动科技进步的重要驱动力,在物理、化学、生物、材料、医学、生命科学等学科领域产生了广泛并深远的影响。衍射现象作为光波的固有属性,限制了光学成像系统的分辨率,如何突破衍射极限、提高成像系统分辨率成为当今科学研究的热点、难点问题。目前扫描近场光学显微镜、负折射率超透镜、受激辐射损耗显微镜等超分辨成像技术在显微成像、微纳光刻等方面取得了一定进步,然而它们无法用于目标处于无穷远时的望远模式。近年来,超振荡现象利用光场的精细干涉行为,在远场局部区域可以产生超出光场最高空间频率的信息,这种现象可以用于望远成像系统,实现超分辨成像,但是却面临着工作波长带宽窄、能量效率低等问题。针对望远模式下超分辨成像以及超振荡光场的窄带宽问题,本论文开展了基于超振荡光场的远场超分辨成像原理和方法研究,论文研究内容主要包括:1、设计和搭建了一种实时、无需后续数据处理、非相干的超分辨望远成像系统,建立了局部光学传递函数模型,阐述了超振荡现象在望远成像模式下超分辨成像机理,实验上获得了0.55倍衍射极限的成像分辨率,测试了系统对离轴物体、复杂物体的超分辨成像效果,同时实现了大目标物体的拼接成像,拓展了超振荡成像视场。2、提出了一种宽带超振荡透镜的设计方法,采用亚波长矩形孔结构的相位调制机理来构建超振荡相位,其独特的相位调制特性保证了不同波长下结构表面处超振荡相位的无色散性,同时分析了不同波长下宽带超振荡透镜产生的轴向焦移现象和超振荡焦斑的变化规律,实验上验证了可见光~近红外波段范围内0.674倍衍射极限的宽带聚焦效果。3、针对宽带超振荡透镜的轴向色差问题,提出了两种消轴向色差超振荡器件的设计方法:第一种采用亚波长矩形孔结构频率响应特性配合器件分区方式,理论上实现了双波长消轴向色差超衍射聚焦;第二种在传统消色差透镜基础上,结合亚波长矩形孔结构宽带的相位调制特性,实现了宽带工作波长范围内消轴向色差超分辨成像。实验上,在中心波长450 nm、550 nm、650 nm以及波长带宽40 nm的照明光场下,验证了器件的宽带超衍射聚焦效果和超分辨成像性能;同时验证了器件的白光超分辨成像性能。
[Abstract]:The development of imaging technology is an important driving force for the advancement of science and technology. It has a wide and far-reaching influence in the fields of physics, chemistry, biology, materials, medicine, life sciences and so on. It limits the resolution of optical imaging system, how to break through the diffraction limit, and how to improve the resolution of imaging system has become a hot and difficult problem in current scientific research. At present, scanning near-field optical microscope, negative refractive index super-lens, Superresolution imaging techniques, such as stimulated radiation loss microscopy, have made some progress in the fields of microscopic imaging and micro-nano lithography. However, they cannot be used in the long-range mode of target at infinity. In recent years, Using the fine interference behavior of the light field, hyperoscillation can produce information beyond the maximum spatial frequency of the light field in the local region of the far field. This phenomenon can be used in the telescopic imaging system to realize super-resolution imaging. However, it is faced with the problems of narrow wavelength band and low energy efficiency. In this paper, the principle and method of far-field super-resolution imaging based on superoscillatory light field are studied. The main contents of this thesis include: 1, designing and building a real-time, non-coherent super-resolution telescopic imaging system without subsequent data processing. The local optical transfer function model is established, and the super-resolution imaging mechanism of the superoscillation phenomenon in the telescopic imaging mode is described. The imaging resolution of the diffraction limit of 0.55 times is obtained experimentally, and the off-axis object of the system is tested. The super-resolution imaging effect of complex objects is achieved, and the splicing imaging of large target objects is realized, and the field of view of hyperoscillation imaging is expanded. A design method of wideband ultra-oscillating lens is proposed. The phase modulation mechanism of the subwavelength rectangular hole structure is used to construct the superoscillatory phase. Its unique phase modulation characteristic ensures the non-dispersive property of the superoscillatory phase at the surface of the structure at different wavelengths. At the same time, the phenomenon of axial focal shift and the variation of superoscillatory focal spot produced by broadband ultra-oscillating lens at different wavelengths are analyzed. The wide band focusing effect of 0.674 times diffraction limit in the range of visible light to near infrared band is verified experimentally, and the axial chromatic aberration of broadband ultra-oscillating lens is discussed. In this paper, two design methods of achromatic superoscillator are presented. Firstly, the double wavelength achromatic hyperdiffraction focusing is realized theoretically by using the subwavelength rectangular hole structure frequency response characteristic and the device partition method. Based on the traditional achromatic lens and the phase modulation characteristics of the subwavelength rectangular hole structure, the second method is used to realize the axial achromatic super-resolution imaging in the wide band working wavelength range. In the illumination field with a central wavelength of 450 nm or 550 nm and a wavelength bandwidth of 40 nm, the wide-band ultra-diffraction focusing effect and super-resolution imaging performance of the device are verified, and the white light super-resolution imaging performance of the device is also verified.
【学位授予单位】：中国科学院研究生院(光电技术研究所)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TP391.41

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