Classical imaging theory of a microlens with super-resolution

Abstract

Super-resolution in imaging through a transparent spherical microlens has attracted lots of attention because of recent promising experimental results with remarkable resolution improvement. To provide physical insight for this super-resolution phenomenon, previous studies adopted a phenomenological explanation mainly based on the super-focusing effect of a photonic nanojet, while a direct imaging calculation with classical imaging theory has rarely been studied. Here we theoretically model the imaging process through a microlens with vectorial electromagnetic analysis, and then exclude the previously plausible explanation of super-resolution based on the super-focusing effect. The results showed that, in the context of classical imaging theory subject to the two-point resolution criterion, a microlens with a perfect spherical shape cannot achieve the experimentally verified sub-100 nm resolution. Therefore, there must be some other physical mechanisms that contribute to the reported ultrahigh resolution but have not been revealed in theory.

Combination of scanning probe technology with photonic nanojets

“…3a, in order to simulate the formation of a virtual image. The position of maximum intensity of this field was considered to be the virtual image plane 32 . As it can be observed in Fig.…”

Experimental imaging properties of immersion microscale spherical lenses

“…One channel transforms the small-k Fourier components, while the other transforms the large-k Fourier components. As the physical mechanism behind the microscale lens imaging remains to be further revealed20, our findings will advance the understanding of the super-resolution imaging mechanisms in microscale lenses.…”

Role of the immersion medium in the microscale spherical lens imaging

“…Among these studies, the microsphere lenses are immersed or semi-immersed in a medium in many cases. Compared to the well-studied solid immersion microscale lenses, the role of the immersion medium in the microscale lens imaging remains to be further revealed [18][19][20]. Our recent experimental results reveal that when a microsphere lens is semi-immersed in a medium, it can intercept more large-k Fourier components of the object, and it has two image channels [21].…”