Super-resolution by converting evanescent waves in microsphere to propagating and transfer function from its surface to nano-jet

TL;DR

This paper investigates how microspheres can convert evanescent waves into propagating waves, enabling super-resolution imaging of fine structures by analyzing wave transmission and transfer functions.

Contribution

It introduces a detailed analysis of evanescent wave conversion using Helmholtz equations and boundary conditions, providing a new understanding of super-resolution mechanisms.

Findings

Evanescent waves are effectively converted to propagating waves via microsphere interactions.

The transfer function describes how spatial modes are convolved to enhance resolution.

The method improves imaging resolution beyond traditional limits.

Abstract

The EM waves transmitted through a thin object with fine structures is observed, by microsphere located above the object. While the waves include both evanescent and propagating waves, the high resolution is obtained by the evanescent ones, including the information on the fine structures of the object. Description of this process is divided into two parts: a) The super resolution is analyzed by using Helmholtz equation for the evanescent waves transmitted from the object to the microsphere surface. b) Using boundary condition, the electric fields on the inner surface of the microsphere includes both the evanescent and propagating waves. The transmission of these waves to a nano jet is produced by a transfer function, including convolution between the spatial modes of the evanescent waves with those of the microsphere, which increases the conversion of the evanescent waves to propagating waves, and thus increase the resolution.