Ultra-narrow photonic nanojets through a glass cuboid embedded in a dielectric cylinder

Abstract

A glass cuboid, embedded inside a dielectric cylinder is studied when illuminated with a monochromatic plane wave. A photonic nanojet (PNJ) with a full-width at half-maximum (FWHM) waist of around 0.25λ is obtained outside the external surface of the cuboid. The influence of the parameters of a square section cuboid is studied. Three particular phenomena can be obtained and are discussed: an ultra-narrow PNJ on the external surface of the cuboid, a long photonic jet and the excitation of whispering gallery modes (WGMs). A parametric study, over the width and the height of a rectangular section cuboid, shows that these parameters can be used to control the photonic jet properties. We also study several other geometries of the insert, which shows that the key parameter is the refractive index of the inserted material. Finally, we show that by changing the incident angle we can obtain a curved photonic jet.

Recent Trends in Optical Manipulation Inspired by Mesoscale Photonics and Diffraction Optics

“…The simulations of a multifocal curved beam based on SiO2 microsphere with a diameter of 433λ (which J of Biomedical Photonics & Eng 6(2) 20 Jun 2020 © J-BPE 020301-4 does not meet the mesoscale condition and goes beyond the range of PNJ effect existence) in the optical waveband show that it is possible to control the curvature of the beam by adjusting the relative position between an off-axis Gaussian beam and a spherical particle [40]. The PH through a structured dielectric cylinder with embedded a glass cuboid was discussed in [41] based on numerical simulations. Furthermore, specially designed five-layer dielectric cylinder allows to produce double PHs [42].…”

All-dielectric concentration of electromagnetic fields at the nanoscale: the role of photonic nanojets

“…103 This device is similar to the dielectric cuboids being tested in various illumination modes. [104][105][106][107][108] The dielectric cube can produce an asymmetric phase anomaly and Gouy phase shi at the terahertz frequency, which cannot be explained simply as an analogy to a lens focusing a Gaussian beam. 109 See the cube and experimental results in Fig.…”

Generation of Photonic Hooks from Patchy Microcylinders

“…PHs can be effectively generated from dielectric particles with asymmetric geometries, such as dielectric trapezoids [14,15] and dielectric cylinders with glass cuboids inside [18], or by using particles with an asymmetric distribution of refractive index (RI), such as Janus particles [19], Janus microbar [20], and so forth. Rotating the particles or adjusting the shape of the particles can effectively change the characteristics of the generated PHs [19].…”