Photonic nanojets with mesoscale high-index dielectric particles

Abstract

In this work, we demonstrate the ability of high-index dielectric particles immersed in air to generate photonic nanojets with extreme resolution (~0.06λ0).Both 2D (cylindrical) and 3D (spherical) particles are analyzed and their profile is truncated using the Weierstrass formulation for solid immersion lenses to produce a photonic nanojet at the output surface under planewave illumination. Their focusing capability is evaluated in terms of the spatial resolution achieving subwavelength values of ~0.14λ0 and ~0.06λ0, for a truncated cylinder and sphere respectively. The capability of the truncated sphere to enhance the backscattering produced by two small metallic spherical scatterers placed near the photonic nanojet is evaluated by using a scanning-probe microscopy configuration. The imaging capabilities of this technique are also analyzed by moving the metallic spheres in the transversal plane where the photonic nanojet is produced. The results here presented improve greatly the typical resolution of photonic nanojets generated with dielectric particles with small index contrast. In addition, the highindex material allows using mesoscale particles, leading to a more compact setup.These results may find applications in areas such as microscopy, imaging and sensing devices where a subwavelength resolution below the diffraction limit is needed.

Raman scattering enhancement of dielectric microspheres on silicon nitride film

“…Due to this effect, it is possible that our results of the simple orbital light interference model shown here are not in complete accord with the Raman spectral waveform from the experiment. In addition to this, the effect of the photonic nanojet between the sphere and the SiN film may also be significant 34 , 35 . In the photonic nanojet, the focused light is directionally emitted from a very small region of the contact surface between the sphere and the SiN film, and this effect may form a large Raman amplitude.…”

Photonic Nanojet Generation Using Integrated Silicon Photonic Chip with Hemispherical Structures

“…At refractive index 𝑛 ≥ 1.74, a drastic increase in LPNJ could be seen. This happened because at those indices, the effective refractive index of the dome was approaching the small index contrast limit (𝑛 < 2) [19,21]. The electric field intensity normalized to 𝐼 𝑜𝑓 𝑛 = 2.05, along the length of PNJ is shown in Figure 5g.…”

“…Their length reduced microcylinder was able to generate narrow PNJ outside the particle. Pacheco-Peña studied the PNJ formation in a high refractive index microsphere cleaved to expose the PNJ [19]. A high refractive index cylinder cleaved to expose the PNJ was investigated by Zhen et al [20].…”

Constructive and Destructive Interference of Kerker-type Scattering in an Ultra-thin Silicon Huygens Metasurface

“…We fill this gap experimentally, numerically and semi-analytically using a dielectric metasurface fabricated from a common silicon-on-insulator wafer. Our study on the effect of substrate may guide the scattering application in photonic nanojets lithography [21] or photonic nanojets design [22].…”