Super-enhancement focusing of Teflon sphere

TL;DR

This paper demonstrates a super-enhancement focusing effect in Teflon spheres at specific sizes, achieving up to 4000 times stronger field intensity and potential to surpass diffraction limits in terahertz applications.

Contribution

It analytically reveals the super-enhancement focusing phenomenon in Teflon spheres and identifies the key scattering mode responsible for this effect.

Findings

Achieves up to 4000 times field intensity enhancement.

Identifies the dominant single order mode causing super-enhancement.

Shows potential to overcome diffraction limit in terahertz focusing.

Abstract

A Teflon (Polytetrafluoroethylene, PTFE) sphere can be used as a focusing lens in the applications of imaging and sensing due to its low-loss property in the terahertz (THz) band. In this paper, we analytically calculated field intensities and focusing parameters for Teflon spheres at different low-loss levels and then discovered a super-enhancement focusing effect in the spheres with particular size parameters, which can stimulate about 4000 times stronger field intensity than that for incident radiation as well as the great potential of overcoming diffraction limit despite high sensitivity to the magnitude of Teflon loss. A subsequent analysis of scattering amplitudes proved that the strong scattering of a single order mode in the internal electric or magnetic field is the main factor causing this phenomenon.