Due to the wave nature of light, resolution of optical imaging systems is limited to approximately half of the wavelength. The reason behind this limitation, known as diffraction limit, is the loss of information contained in evanescent waves at the far-field region. Here, we propose a new method to retrieve the information contained in evanescent waves in far field region resulting in a novel sub-wavelength imaging technique which can go beyond the diffraction limit. We theoretically prove that using interference of waves, between the target field and reference and reconstruction waves, one can apply a shift to the angular spectrum of the target field and convert a range of evanescent waves into propagating modes. Moreover, we demonstrate how these converted waves can be distinguished in far-field from other existing modes. Unlike previously developed sub-wavelength imaging techniques, the proposed method does not require either fluorescent materials or complex nano-structures to realize evanescent-to-propagating wave conversion. The performance of the method is numerically investigated illustrating a resolution of one-seventh of the working wavelength, which is much beyond the diffraction limit. The proposed technique can significantly simplify sub-wavelength imaging paving the road to develop practical low cost super-resolution imaging systems.

中文翻译：

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使用波干涉超越衍射极限的远场成像

由于光的波动性，光学成像系统的分辨率被限制在大约波长的一半。这种限制背后的原因称为衍射极限，是远场区域的倏逝波中包含的信息丢失。在这里，我们提出了一种新方法来检索远场区域的倏逝波中包含的信息，从而产生一种可以超越衍射极限的新型亚波长成像技术。我们从理论上证明，利用波在目标场与参考波和重建波之间的干涉，可以对目标场的角谱应用偏移并将一系列渐逝波转换为传播模式。此外，我们演示了如何在远场中将这些转换波与其他现有模式区分开来。与以前开发的亚波长成像技术不同，所提出的方法不需要荧光材料或复杂的纳米结构来实现渐逝波到传播波的转换。对该方法的性能进行了数值研究，说明了工作波长的七分之一的分辨率，这远远超出了衍射极限。所提出的技术可以显着简化亚波长成像，为开发实用的低成本超分辨率成像系统铺平了道路。这远远超出了衍射极限。所提出的技术可以显着简化亚波长成像，为开发实用的低成本超分辨率成像系统铺平了道路。这远远超出了衍射极限。所提出的技术可以显着简化亚波长成像，为开发实用的低成本超分辨率成像系统铺平了道路。