arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2001.00237physics.opticsphysics.app-ph
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论倏逝波成像的基本局限性

On the fundamental limitations of imaging with evanescent waves

Alexander Y. Piggott, Logan Su, Jan Petykiewicz, Jelena Vučković

摘要:

人们对使用倏逝波来克服衍射极限的成像和聚焦方案(诸如采用负折射率材料或双曲超材料的那些)有着极大的兴趣。所有这些方案的基本问题是,倏逝波在成像系统和样品之间迅速衰减,导致极弱的场强。使用的熵定义的光斑尺寸仍然定义为任意光束轮廓,我们推导出严格的界限上的倏逝衰减。特别是,我们表明,衰减长度只有$w / πe \approx 0.12 w$,其中$w$是在焦平面上的光斑宽度,或$\sqrt{A} / 2 e \sqrtπ \approx 0.10 \sqrt{A}$,其中$A$是光斑面积。因此,实际的倏逝波成像方案将最有可能限于小于或等于光斑宽度的焦距。

英文摘要:

There has been significant interest in imaging and focusing schemes that use evanescent waves to beat the diffraction limit, such as those employing negative refractive index materials or hyperbolic metamaterials. The fundamental issue with all such schemes is that the evanescent waves quickly decay between the imaging system and sample, leading to extremely weak field strengths. Using an entropic definition of spot size which remains well defined for arbitrary beam profiles, we derive rigorous bounds on this evanescent decay. In particular, we show that the decay length is only $w / πe \approx 0.12 w$, where $w$ is the spot width in the focal plane, or $\sqrt{A} / 2 e \sqrtπ \approx 0.10 \sqrt{A}$, where $A$ is the spot area. Practical evanescent imaging schemes will thus most likely be limited to focal distances less than or equal to the spot width.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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