Superoscillation focusing with suppressed sidebands by destructive interference

Optical superoscillation, a phenomenon that the local optical field can oscillate much faster than that allowed by its highest harmonic, can significantly overcome the Abbe diffraction limit. However, as the spot size is compressed below the superoscillation criteria of 0.38λ/NA, huge sidebands will inevitably appear around the central lobe with intensity hundreds of times higher than that of the central lobe. Here, we propose an approach to realize superoscillation by using destructive interference. The central lobe size can be compressed beyond the superoscillation criteria without formation of strong sidebands by destructive interference between focused fields. Such a super-resolution metalens can find its application in label-free far-field super-resolution microscopy.

光学超振荡是一种局部光场的振荡速度可以比其最高谐波所允许的速度快得多的现象，它能够显著突破阿贝衍射极限。然而，当光斑尺寸被压缩到低于0.38λ/NA的超振荡标准时，在中心瓣周围不可避免地会出现巨大的边带，其强度比中心瓣高数百倍。在此，我们提出一种利用相消干涉实现超振荡的方法。通过聚焦场之间的相消干涉，中心瓣尺寸可以被压缩到超振荡标准以下，且不会形成强烈的边带。这种超分辨超构透镜可应用于无标记远场超分辨显微镜中。