Cover story: Luo H, Hou M D, Xu L, et al. Optical fiber integrated unlabeled differential super-resolution microscopic imaging system[J]. Opto-Electron Eng, 2023, 50(12): 230181

Far-field super-resolution microscopic imaging technology based on fluorescent labels opened a gate to the microscopic world, which has become an important tool in the research of modern medicine and life science. However, the development of far-field unlabeled super-resolution microscopy is relatively slow. Here, an integrated differential microscopic imaging method using optical fiber devices is proposed in this article. The generation of hollow spots in the differential imaging system is realized by a special fiber mode selection coupler (MSC). The problem of strict alignment between hollow and solid spots is naturally solved in this method. A highly integrated label-free microscopic imaging system was established. In experiments, gold particles with a diameter of 150 nm and unlabeled polymer lines with a minimum spacing of about 50 nm were imaged to test the imaging system. The resolution of the imaging system shows great improvement compared to conventional scanning confocal microscopy.