The role of near-field diffraction in photonic nanojet formation

TL;DR

This paper demonstrates that photonic nanojets are formed by near-field diffraction, not sub-diffraction modes, and can be tailored by modifying the optical environment, using a simplified diffraction model and numerical simulations.

Contribution

It provides a diffraction-based explanation for photonic nanojet formation and shows how to control nanojet features through environmental modifications.

Findings

Nanojets are central bright maxima in diffraction patterns.

Nanojet features can be tailored by changing the optical environment.

Nanojets are adequately described by diffraction theory, not sub-diffraction modes.

Abstract

In this paper, we show the photonic nanojet is the central bright maxima in focused near-field diffraction pattern. Using a simplified Huygens-Fresnel model, and using numerical simulations, we generate photonic nanojets from curved interfaces between media of different refractive indices and study the length, width, and peak intensity of the resultant photonic nanojet. We confirm that photonic nanojets are not sub-diffraction optical modes and are adequately described using diffraction theory. We also show how modifying the optogeometric environment can be used to tailor relevant features of the nanojets in general.