EurekAlert June 24, 2021
Optical superoscillation refers to a phenomenon of a wave packet that can oscillate locally faster than its highest Fourier component, which potentially produces an extremely localized wave in the far field. It provides an alternative way to overcome the diffraction limit and improve the resolution of an optical microscopy system. However, the optical superoscillatory waves are inevitably accompanied by strong side lobes, which limits their fields of view and, hence, potential applications. Researchers in China report both experimentally and theoretically a new superoscillatory wave form, which not only produces significant feature size down to deep subwavelength, but also completely eliminates side lobes in a particular dimension. They demonstrated a new mechanism for achieving such a wave form based on a pair of moonlike sharp-edge apertures. The resultant superoscillatory wave exhibits Bessel-like forms, hence allowing long-distance propagation of subwavelength structures. The result facilitates the study of optical superoscillation and on a fundamental level eliminates the compromise between the superoscillatory feature size and the field of view…read more. Open Access TECHNICAL ARTICLEÂ
A pair of moonlike sharp-edge apertures enables generation of diffractive focusing light spot sized within the optical diffraction limit, while eliminating side waves along the symmetric cut. Credit: Yanwen Hu.