Chen Junjie, Hu Yanwen, Yin Hao, Li Zhen, Chen Zhenqiang, Fu Shenhe
Opt Express. 2022 Oct 24;30(22):39510-39519. doi: 10.1364/OE.470120.
When it comes to the high-spatial-frequency electromagnetic waves, we usually think of them as the evanescent waves which are bounded at the near-field surface and decay along with propagation distance. A conventional wisdom tells us that the high-spatial-frequency waves cannot exist in the far field. In this work, we show, however, that these high-spatial-frequency waves having wavenumbers larger than the incident one can propagate freely to the far-field regions. We demonstrate theoretically a technique, based on an abrupt truncation of the incident plane wave, to generate these intriguing waves. The truncation functions describing the slit and the complementary slit are considered as typical examples. Our results show that both the slit structures are able to produce the high-spatial-frequency wave phenomena in the far field, manifested by their interference fringes of the diffracted waves. This work introduces the high-spatial-frequency propagating waves. Therefore, it may trigger potential investigations on such an interesting subject, e.g., one may design delicate experiment to confirm this prediction. Besides, it would stimulate potential applications such as in superresolution and precise measurement.
当涉及到高空间频率的电磁波时，我们通常认为它们是在近场表面受限并随传播距离衰减的倏逝波。传统观念告诉我们，高空间频率波在远场中无法存在。然而，在这项工作中，我们表明，这些波数大于入射波数的高空间频率波能够自由传播到远场区域。我们从理论上证明了一种基于入射平面波突然截断的技术，以产生这些有趣的波。描述狭缝和互补狭缝的截断函数被视为典型示例。我们的结果表明，两种狭缝结构都能够在远场中产生高空间频率波现象，表现为它们衍射波的干涉条纹。这项工作引入了高空间频率传播波。因此，它可能引发对这一有趣主题的潜在研究，例如，人们可以设计精密实验来证实这一预测。此外，它还将刺激诸如超分辨率和精确测量等潜在应用。
