Determination of microsphere-lens magnification using micro-robotic scanning superlens nanoscopy

Abstract

Microsphere-assisted nanoscopy has shown great potential in recent developments in the field of super-resolution imaging. The precise control of microspheres is leading to new discoveries that can help verify the theories behind the super-resolution imaging mechanism. However, microsphere imaging involves multiple planes that have different magnification factors, which affect the determination of the overall resolution of the image. In this study, we present a flexible probe-lens assembly scheme that uses a barium titanate glass microsphere, as well as various scanning stages that can be used to freely investigate the sample surface and perform large-area super-resolution imaging (80 μm × 60 μm). The obtained resolution using this assembly under water immersion condition is 130 nm. By investigating the relationship between the magnification factors and the corresponding focus position of the different feature patterns, a remarkable difference in the focusing characteristics between arbitrary and periodic patterns was revealed. Results demonstrate the universality of the proposed method for the quantitative selection of the best focused plane and determination of the corresponding magnification factor and resolution of a microsphere virtual image for any feature pattern. The findings provide additional insights into the interpretation of arbitrary nanostructures through 3D optical imaging.