Specular-reflection photonic hook generation under oblique illumination of a super-contrast dielectric microparticle

TL;DR

This paper explores the generation of a novel optical phenomenon called the 'specular reflection photonic hook' using super-contrast dielectric microparticles under oblique illumination, expanding understanding of photonic nanojet formation.

Contribution

It introduces the concept of a curvilinear optical field localization called the 's-Hook' and analyzes its formation under different illumination and mirror configurations.

Findings

Discovery of the 'specular reflection photonic hook' phenomenon.

Identification of two regimes of s-Hook formation.

Numerical demonstration of s-Hook behavior in 2D and 3D microparticles.

Abstract

The possibility of overcoming the critical condition for localized photonic nanojet upon plane optical wave diffraction at mesoscale dielectric particle, which is commonly known as "the refractive index contrast is less than two", was recently reported in our works. To this end, the novel geometrical scheme of photonic nanojet generation in "reflection mode" was proposed based on a super-contrast microparticle (n~2) placed near a flat mirror. In this paper, through the numerical FDTD calculations of optical near-field structure of 2D and 3D dielectric microparticles (cylinder, sphere) we extend our considerations to the case of oblique particle-at-mirror illumination and present new physical phenomena arising in the considered photonic geometry. Those are the generation of a quasi-retrograde photonic nanojet following the inclined particle illumination and the formation of a curvilinear spatial region of optical field localization in the form of a "specular reflection photonic hook" (s-Hook). Two different regimes of s-Hook formation are analyzed by changing the direction of light incidence and by flat mirror rotation.