Department of Electrical and Computer Engineering, University of Victoria, Victoria, British Columbia V8P 5C2, Canada.
Opt Lett. 2012 Mar 1;37(5):912-4. doi: 10.1364/OL.37.000912.
Perfect lensing using negative refractive index materials and radiationless electromagnetic interference both provides extreme subwavelength focusing by "amplifying" evanescent wave components that are usually lost. This Letter provides a relation between the achievable focus spot size, the amplification available, and the focal length. This may be considered as a revised version of Abbe's diffraction limit for focusing systems that have evanescent wave amplification. It is useful in comparing the amplification achieved in various subwavelength focusing implementations as well as determining when it is better to use existing near-field techniques, such as simple diffraction from an aperture or slit, than to attempt complicated superfocusing.
利用负折射率材料和无辐射电磁干扰进行完美聚焦，都可以通过“放大”通常会丢失的倏逝波分量来实现极端亚波长聚焦。本文给出了可实现的焦点光斑尺寸、可用的放大倍数和焦距之间的关系。这可以被看作是阿贝衍射极限的修订版本，适用于具有倏逝波放大的聚焦系统。它在比较各种亚波长聚焦实现中的放大效果以及确定何时使用现有的近场技术（例如孔径或狭缝的简单衍射）更好，而不是尝试复杂的超聚焦时非常有用。
