State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Technology, Zhejiang University, Hangzhou 310027, China; Corresponding author.
Yiming Li
Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen 518055, China
Shuang Fu
Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen 518055, China
Yanghui Li
College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310018, China
Yingke Xu
Key Laboratory for Biomedical Engineering & Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular Detection Technology and Medicinal Effectiveness Appraisal, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou 310027, China
Cuifang Kuang
State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Technology, Zhejiang University, Hangzhou 310027, China
Xu Liu
State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Technology, Zhejiang University, Hangzhou 310027, China
Since the 1990s, continuous technical and scientific advances have defied the diffraction limit in microscopy and enabled three-dimensional (3D) super-resolution imaging. An important milestone in this pursuit is the coherent utilization of two opposing objectives (4Pi geometry) and its combination with super-resolution microscopy. Herein, we review the recent progress in 4Pi nanoscopy, which provides a 3D, non-invasive, diffraction-unlimited, and isotropic resolution in transparent samples. This review includes both the targeted and stochastic switching modalities of 4Pi nanoscopy. The schematics, principles, applications, and future potential of 4Pi nanoscopy are discussed in detail.
