Husakou A, Herrmann J
Opt Express. 2004 Dec 27;12(26):6491-7. doi: 10.1364/opex.12.006491.
Usual optical elements cannot focus a light beam to a spot with diameter smaller than half of the wavelength of the light; however overcoming this limit is of great importance in several applications in high-tech, such as optical lithography or magneto-optical date storage and numerous other fields of science and industry. Here we show that it is possible to focus light to spots below the diffraction limit (superfocusing) by the combination of two main elements: one which creates weak near-field evanescent components of the beam, like a wavelength-scale aperture, and an amplifier of these evanescent fields, like a slab of a photonic crystal with negative refraction.
普通光学元件无法将光束聚焦到直径小于光波长一半的光斑；然而，突破这一限制在高科技的若干应用中，如光学光刻或磁光数据存储以及众多其他科学和工业领域，具有极其重要的意义。在此我们表明，通过两种主要元件的组合，可以将光聚焦到低于衍射极限的光斑（超聚焦）：一种是产生光束的弱近场倏逝分量的元件，如波长尺度的孔径，另一种是这些倏逝场的放大器，如具有负折射的光子晶体平板。
