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中红外热成像系统是通过探测物体本身的辐射进行成像,不需要外部光源。而传统的中红外热成像系统体积大,不利于小型化。本文基于传输相位理论,采用时域有限差分(FDTD)法,使用FDTD软件计算仿真,探究了不同的单元半径、纳米柱高度及单元周期对相位延迟及透过率的影响,并且针对不同的纳米柱半径,利用传输相位调控实现中红外(3~5μm)波长下全介质硅材料的宽带消色差超透镜设计。其数值孔径为0.24,仿真焦距值为147.3μm,半峰全宽(FWHM)为8.11μm,透镜透过率达到70%。设计的超透镜不仅体积小、质量轻、全波长聚焦效率可达到54%,而且为平面透镜,因此易于光学系统集成,在红外成像、红外夜视仪、红外遥感等技术中展现出广阔的应用前景。 相似文献
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单扫描时空编码磁共振成像是一种新型超快速磁共振成像技术,它对磁场不均匀和化学位移伪影有较强的抵抗性,但是其固有的空间分辨率较低,因此通常需要进行超分辨率重建,以在不增加采样点数的情况下提高时空编码磁共振图像的空间分辨率.然而,现有的重建方法存在迭代求解时间长、重建结果有混叠伪影残留等问题.为此,本文提出了一种基于深度神经网络的单扫描时空编码磁共振成像超分辨率重建方法.该方法采用模拟样本训练深度神经网络,再利用训练好的网络模型对实际采样信号进行重建.数值模拟、水模和活体鼠脑的实验结果表明,该方法能快速重建出无残留混叠伪影、纹理信息清楚的超分辨率时空编码磁共振图像.适当增加训练样本数量以及在训练样本中加入适当的随机噪声水平,有助于改善重建效果. 相似文献
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压缩感知算法可以利用信号的稀疏性较好地分辨出两个相距较远的目标,但是当两个目标相距较近时仅利用压缩感知算法,分辨性能较差;另外,当分辨目标为硬散射体时,由于偶极散射的影响,分辨性能也会变得较差。考虑到上述两个问题,该文提出了以下解决方案:针对第一个问题,该文将声学超透镜和压缩感知算法进行结合;针对第二个问题,该文提出在压缩感知算法中考虑偶极散射分量的影响。根据上述方案进行仿真,仿真结果证明了在加入声超透镜并考虑偶极散射以后,硬散射体目标在相距较近时实现了较好的分辨率。 相似文献
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微透镜辅助显微镜实现超分辨成像观测,具有免标记、无损伤、实时、定域和环境兼容性好等优势.液体微透镜阵列具有均一、易操控的特性,可实现无复杂机械扫描与驱动的超分辨成像.然而,简单高效地精确控制成像距离是微透镜实现超分辨成像的关键技术挑战.本文利用紫外曝光技术,实现了光盘上光刻胶微孔深度的均一性.结合液体自组装技术,在微孔中填充甘油液滴,保证微透镜辅助超分辨的成像距离.在光学显微镜下实现了对226 nm光栅栅线的可重构超分辨观测与1.59倍成像放大.本文从液体微透镜的阿贝显微成像原理出发,通过理论与模拟解释了液体微透镜的成像放大与超分辨特性.由此可见,光盘上集成的液体微透镜阵列在光学纳米测量与传感等器件中展现了巨大的应用潜力. 相似文献
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超透镜光刻技术是一种很有前景的纳米结构成像技术,由于其具有可以克服衍射极限的能力,直到2005年,张翔和他的同事在365 nm紫外线波长下成功的对一排纳米线和刻在高分子膜上的四个字母NANO实现了超分辨成像,分辨率高达1/6入射波长。通过传递矩阵方法优化出超透镜结构,并通过选择适当的材料和设计在超透镜结构中的每个层的厚度以及合理的优化实验等方法制备一个新的超透镜结构,利用这种超透镜结构实现了周期性纳米结构及孤立纳米结构的亚波长成像。实验结果表明,对于周期性的纳米结构,其图像分辨率达到100 nm,而孤立结构的分辨率低于50 nm,小于入射波长的1/7。 相似文献
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光学成像系统中有限孔径对光波的衍射,使得光学显微成像技术的分辨率受到"衍射极限"限制而无法进一步提高.自1873年E.K.Abbe提出该问题以来,衍射极限就一直是学术界研究的热点.近年来,随着高强度激光、高灵敏探测器等光电器件研制技术以及新型荧光探针开发等相关领域的快速发展,光学显微技术衍射极限问题的研究迎来了新的契机,超分辨显微成像技术(super-resolution microscopy.SRM)在近十年内取得了令人瞩目的巨大成就.本文从空域和频域角度回顾了衍射极限分辨率的基本原理,并据此对目前常见的各种SRM技术"绕过"衍射极限提高分辨率的机理给予了详解,同时介绍了各类技术的发展动态和研究方向;作为SRM的一个新的重要的发展趋势,本文详细介绍了超分辨关联显微技术的最新研究进展,包括SRM与活细胞实时荧光显微、荧光寿命显微、光谱测量和成像、电子显微、原子力显微、质谱技术等的关联,着重讨论了各类超分辨关联显微技术的作用和意义;最后,对SRM技术和超分辨关联显微技术的未来发展方向进行了展望. 相似文献
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为了进一步认知复杂环境中的细胞生物学过程,研究人员发展了各种各样的生物成像技术。在这些技术中,生物荧光成像因简单的成像条件以及对生物样品的相容性而得到了广泛的发展。然而,传统的荧光成像技术受到了光学衍射极限的限制,无法分辨低于200 nm的空间结构,阻碍了对亚细胞结构的生物学过程研究。超分辨荧光显微镜技术突破了传统光学衍射对成像分辨率的限制,能够获取纳米尺度的细胞动态过程。除了对传统的宽场荧光显微镜框架的改进及升级改造之外,目前典型的超分辨成像显微镜技术通常依赖于荧光探针材料的光物理性质。常用的荧光探针材料包括荧光蛋白、有机荧光分子和纳米荧光材料等。本文介绍了几种主流的超分辨荧光显微成像技术并总结了已经成功应用到超分辨生物荧光成像中的荧光探针材料的应用进展。 相似文献
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We present an implementation of localization based three-dimensional super-resolution imaging on a regular microscope. We retain the original arc lamp as the photoactivation light source, and incorporate an inexpensive diode laser for imaging. As alterations to the standard microscope is minimal, this optical setup can be easily adapted in a typical research laboratory and even undergraduate teaching experiments, providing an inexpensive system for students and research scientists who require such super resolution capabilities. With this simple design, a spatial resolution of better than 40 nm at a reasonable frame rate has been achieved, adequate for most routine applications. 相似文献
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Acoustic imaging is a standard technique for mapping acoustic source powers and positions from limited observations on microphone sensors, which often causes an ill-conditioned inverse problem. In this article, we firstly improve the forward model of acoustic power propagation by considering background noises at the sensor array, and the propagation uncertainty caused by wind tunnel effects. We then propose a robust super-resolution approach via sparsity constraint for acoustic imaging in strong background noises. The sparsity parameter is adaptively derived from the sparse distribution of source powers. The proposed approach can jointly reconstruct source powers and positions, as well as the background noise power. Our approach is compared with the conventional beamforming, deconvolution and sparse regularization methods by simulated, wind tunnel data and hybrid data respectively. It is feasible to apply the proposed approach for effectively mapping monopole sources in wind tunnel tests. 相似文献
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Image super-resolution based on local self-similarity 总被引:4,自引:0,他引:4
A new image super-resolution method based on a codebook mapping is proposed. The codebook mapping represents the internal
relationship between low-and high-frequency image components, and is used for the estimation of highfrequency image components
lost in the sampling process. In the proposed method, codebooks are first generated by the low-and high-frequency image components
of the original image itself that is to be processed. Then, a resultant superresolution image, that is, an enlarged image,
is obtained by combining the estimated high-frequency image components with the low-frequency ones obtained by a typical interpolation-based
method. The effectiveness of the proposed method is verified by comparing it against some conventional methods. 相似文献
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Near-field multiple super-resolution imaging from Mikaelian lens to generalized Maxwell's fish-eye lens 下载免费PDF全文
Yangyang Zhou 《中国物理 B》2022,31(10):104205-104205
Super-resolution imaging is vital for optical applications, such as high capacity information transmission, real-time bio-molecular imaging, and nanolithography. In recent years, technologies and methods of super-resolution imaging have attracted much attention. Different kinds of novel lenses, from the superlens to the super-oscillatory lens, have been designed and fabricated to break through the diffraction limit. However, the effect of the super-resolution imaging in these lenses is not satisfactory due to intrinsic loss, aberration, large sidebands, and so on. Moreover, these lenses also cannot realize multiple super-resolution imaging. In this research, we introduce the solid immersion mechanism to Mikaelian lens (ML) for multiple super-resolution imaging. The effect is robust and valid for broadband frequencies. Based on conformal transformation optics as a bridge linking the solid immersion ML and generalized Maxwell's fish-eye lens (GMFEL), we also discovered the effect of multiple super-resolution imaging in the solid immersion GMFEL. 相似文献
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A far-field optical lithography is developed in this
paper. By designing the structure of a far-field optical superlens,
lithographical resolution can be improved by using a
conventional UV light source. The finite different time domain
numerical studies indicate that the lithographic resolution at 50~nm
line width is achievable with the structure shown in this paper by
using 365~nm wavelength light, and the light can be transferred to a
far distance in the photoresist. 相似文献
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结构光照明显微镜(Structured Illumination Microscopy,SIM)通过结构化照明在频率域以空间混频的方式将物体高频信息载入光学系统的探测通带内实现突破衍射极限的超分辨光学显微成像。SIM凭借其较低的激发光强、对荧光染料的非特异性需求以及快速的宽场成像优势已成为活细胞超分辨光学显微成像方面应用最多的技术。本文系统回顾了SIM的技术进展,对SIM的基本原理与实现方法进了详细的分析,重点介绍了本课题组研发的基于光谱分辨的单光子激发超分辨显微镜和结合自适应光学的双光子激发超分辨显微镜这两种最新的SIM技术,最后简要讨论了SIM技术在生物成像中的应用及未来发展方向。 相似文献