Simulation on Focusing of Bilayer Compound Microsphere for Super Resolution Imaging

The microsphere lens holds significant importance in optical nanoimaging, precision measurement, intelligent sensing, and photolithography. The compound structure represents the most essential method for enhancing the super-resolution imaging performance of microsphere lenses. However, the most of prior researches on compound microsphere lenses have been constrained by concentric spheres and bihedra structure theory. In this study, we have introduced the theory of the photonic nanojet (PNJ) and system spectrum extension, which allowed us to simulate the impact of the inner interface profile of a bilayer compound microsphere lens on diffraction focusing. We discovered that a smaller internal interface radius in bilayer compound microspheres is more favorable for optical nanoimaging. These results offer a reliable foundation for achieving higher precision in nano optical detection in the future.