报告题目：Adaptive Optics Methods in a 4pi Single Molecule Switching Microscope
报告人：Dr. Jingyu Wang, Department of Engineering Science, University of Oxford, 牛津大学工程科学系
Abstract: An adaptive optics (AO) assisted 4Pi single molecule switching (SMS) microscope for ultra-high spatial resolution single molecule imaging will be present. Super-resolution microscopes provide nanometer spatial resolution for cell biological studies; however, the axial resolution of standard SMS microscopes is inferior to the transverse resolution. By using two opposing objective lenses for coherent detection of fluorescent emission, a SMS microscope in 4Pi configuration enables ultra-high axial resolution with an improved signal collection efficiency. Due to the nature of 4Pi imaging, even a moderate sample thickness will inevitably introduce aberrations that affect the focusing performance of the system. More importantly, the aberrations experienced by the two arms of the 4Pi cavity are different and will vary differently as the imaging position moves axially. For these reasons, the axial resolution and imaging efficiency deteriorate quickly with depth in thick samples. This limits the axial imaging range and makes imaging large cells with uncompromised resolution impossible without compensating the depth dependent aberrations. The nature of aberrations in a 4Pi cavity has been described and the effect on the system performance was studied. Based on this knowledge, we demonstrate aberration correction methods using a novel sensorless AO approach. Two deformable mirrors (DM) are employed in the microscope, one for each objective. A compact interferometer is devised for accurate DM calibration and control, and we estimate the aberrations base on imaging metrics. The AO 4Pi SMS microscope is tested in imaging whole biological cells, and it allow a significant larger axial imaging range.
Jingyu Wang, from a Biomedical engineering background, obtained his PhD from Prof. Adrian Podoleanu’s group, University of Kent, working on parallel detection Optical coherence tomography. After that, he switched to the fields of microscopy methods. He built a six-color single molecule fluorescence microscope for DNA repair study in Dr. Neil Kad’s group, in University of Kent. Jingyu joined Prof. Martin Booth’s Dynamic Optics and Photonics group in University Oxford in 2017 as a Post-doctoral Research Scientist. He has been working on applying adaptive optics methods on various microscopes, including 2-photon microscope, Third-Harmonic microscope, light sheet microscope and single molecule localization super-resolution microscope. He recently works on developing a novel adaptive optics method on a 4Pi single molecule switching microscope, with collaboration with Joerg Bewersdorf’s group (Yale, U.S.), Jonas Ries group (EMBL, Germany) and St Johnston’s Group, Cambridge (U.K.).