Here, we show that non-invasive optical nanoscopy can achieve a lateral resolution of 90 nm by using a quasi-2pi-holographic detection scheme and complex deconvolution. We record holograms from different illumination directions on the sample plane and observe subwavelength tomographic variations of the specimen. Nanoscale apertures serve to calibrate the tomographic reconstruction and to characterize the imaging system by means of the coherent transfer function. This gives rise to realistic inverse filtering and guarantees true complex field reconstruction. The observations are shown for nanoscopic porous cell frustule (diatoms), for the direct study of bacteria (Escherichia coli), and for a time-lapse approach to explore the dynamics of living dendritic spines (neurones).
Above: Side-by-side comparisons of resolution in traditional DHM and 2?-DHM.
Marker-free phase nanoscopy: Yann Cotte,Fatih Toy, Pascal Jourdain, Nicolas Pavillon, Daniel Boss, Pierre Magistretti, Pierre Marquet & Christian Depeursinge.Nature Photonics 7, 113–117 (2013)