Label-free 3D super-resolution nanoscope with large field-of-view

Photonic nanojet interferometry (PNI) permits three dimensional (3D) label-free and super-resolution surface characterization. PNI is based on coherence scanning interferometry (CSI), featuring Ångstrom level vertical resolution. Being an optical far-field technique, CSI is diffraction limited and according to the Abbe criteria, can laterally resolve, points that are separated by a few hundred nanometers. We overcame this limitation by using dielectric microspheres that generate photonic nanojets. Now sub 100 nm features can laterally be resolved while preserving the vertical resolution of the CSI system. The microsphere material could be polymer or glass with a diameter between 8 and 12 μm, which limits the field of view (FoV) of the PNI system to ~10 μm2. Here we present a method to increase the FoV of a PNI based device by stitching a sequence of adjacent 3D images. We imaged a recordable Blu-ray Disc (BR-D) using a custom built Mirau type scanning white light interferometer with enhanced lateral resolution. Four 3D super-resolution images with constant 80% overlap, were stitched together using inhouse software. The resulting high fidelity image shows that 45% overlap and the above described procedure could be used to enlarge the FoV of label-free 3D super-resolution imaging systems.