Key Laboratory for Opto-Electronic Technology of Jiangsu Province, Nanjing Normal University, Nanjing 210023, China
Fen Tang
School of Computer and Electronic Information, Nanjing Normal University, Nanjing 210023, China
Lingya Yu
School of Computer Science and Electronic Engineering, Bangor University, Bangor LL57 1UT, UK
Hamid Oubaha
Institute of Information and Communication Technologies, Electronics and Applied Mathematics, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
Darwin Caina
Institute of Information and Communication Technologies, Electronics and Applied Mathematics, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
Songlin Yang
Advanced Photonics Center, Southeast University, Nanjing 210096, China
Sorin Melinte
Institute of Information and Communication Technologies, Electronics and Applied Mathematics, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
Chao Zuo
Smart Computational Imaging Laboratory (SCILab), School of Electronic and Optical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
Zengbo Wang
School of Computer Science and Electronic Engineering, Bangor University, Bangor LL57 1UT, UK
Ran Ye
School of Computer and Electronic Information, Nanjing Normal University, Nanjing 210023, China
The diffraction limit is a fundamental barrier in optical microscopy, which restricts the smallest resolvable feature size of a microscopic system. Microsphere-based microscopy has proven to be a promising tool for challenging the diffraction limit. Nevertheless, the microspheres have a low imaging contrast in air, which hinders the application of this technique. In this work, we demonstrate that this challenge can be effectively overcome by using partially Ag-plated microspheres. The deposited Ag film acts as an aperture stop that blocks a portion of the incident beam, forming a photonic hook and an oblique near-field illumination. Such a photonic hook significantly enhanced the imaging contrast of the system, as experimentally verified by imaging the Blu-ray disc surface and colloidal particle arrays.
