Focal-Plane Extreme Adaptive Optics for Deep Super Resolution Imaging and Nanolithography
Super resolution optical imaging and nanolithography enable nanoscale observation and fabrication, but high order, spatially varying phase and amplitude aberrations in optically heterogeneous media severely limit their performance at depth. Here we introduce focal-plane extreme adaptive optics (FP-ExAO), which moves beyond conventional phase conjugate correction by directly sensing and controlling the focal-plane complex field. This terminal field captures aberrations accumulated throughout the optical system. A state space formulation directly links deformable mirror commands to the focal field, avoiding explicit plane by plane Fourier optics modelling, while information theoretically optimal probing and closed-form control enable rapid field estimation and correction. Cascaded deformable mirrors further enable FP-ExAO to correct coupled phase-amplitude and spatially varying aberrations. In three-dimensional (3D) single molecule localization microscopy (SMLM), FP-ExAO enables imaging to 160 um depth in brain tissue and beyond 60 um in kidney tissue, while maintaining approximately 18 nm localization precision across a 75 um x 75 um corrected field, with a 16-fold larger field of view and more than tenfold faster correction than conventional AO methods. These capabilities meet the imaging requirements for 3D deep tissue optical connectome reconstruction and quantitative super resolution pathology. In stimulated emission depletion (STED) nanolithography, FP-ExAO reduces the minimum written linewidth from 251.1 nm without correction to 88.8 nm at a depth of 160 um in photoresist. FP-ExAO establishes a new adaptive optics paradigm for deep nanoscale optical readout and writing.