Photonic Jet by a Near‐Unity‐Refractive‐Index Sphere on a Dielectric Substrate with High Index Contrast

Abstract

Photonic jets are normally generated in transmission mode and are represented as a spatially localized high-intensity region on the shadow side of a particle-lens, with a background to medium refractive index contrast of 1.3-1.7 while illuminated by a plane wave. Here, a photonic jet is discovered in the opposing plane wave propagation direction and lies in the area in the upper boundary of a near-unity refractive index sphere on a high refractive index dielectric substrate. The redistribution of the power flow is inhibited during the reflected wave passing the near-unity refractive index sphere. This has led to a unique effect on the focus position and shape of the produced photonic jet in reflection mode which can be maximally maintained near the sphere regardless of the modulation of the refractive index for the dielectric substrate material.

Experimental observation of flat focusing mirror based on photonic jet effect

“…The focusing properties from the dielectric cuboid have been evaluated at the fundamental and first frequency harmonics under normal and oblique incidence. The similar results are discussed for hemi-spherical dielectric particle placed on flat metal surface 16 and for a near-unity-refractive-index sphere on a dielectric substrate with high index contrast 17 . Based on PJs formed in the reflection regime, new modifications of a subwavelength, standing-wave optical trap are proposed to stabilize the position of a particle at a certain distance from the surface 18 .…”

Optical Phenomena in Mesoscale Dielectric Particles

“…According to [86], the photonic jet can f in the opposite direction of the incident wave propagation, in using a near-unity-re tive-index particle on a dielectric substrate with high index contrast or a metal subst In this case, the beam width can be less than the diffraction limit. The analysis of the P ting vector distribution shows [88] that this phenomenon is associated with a mul circulation of the power flux in and near the particle. It should be noted that the selec of the refractive index contrast between the particle and the substrate can provide the rameter control of the localized radiation area and its position in both reflected and p agated waves.…”

“…In this case, the beam width can be less than the diffraction limit. The analysis of the Poynting vector distribution shows [88] that this phenomenon is associated with a multiple circulation of the power flux in and near the particle. It should be noted that the selection of the refractive index contrast between the particle and the substrate can provide the parameter control of the localized radiation area and its position in both reflected and propagated waves.…”

Optical phenomena in mesoscale dielectric particles

“…At the same time, the photonic jet formation in the reflected wave allows avoiding several restrictions to the refractive index of the particle material, associated with the area of the photonic jet existence in the propagated radiation [5]. According to [86], the photonic jet can form in the opposite direction of the incident wave propagation, in using a near-unityrefractive-index particle on a dielectric substrate with high index contrast or a metal substrate. In this case, the beam width can less than the diffraction limit.…”