Tunable acoustic hooks from Janus cylinder

[EN] In this paper we present a new way to obtain tunable acoustic hooks. The breaking of the symmetry of the material composition is used for the generation of acoustic hooks from Janus cylinders. This fact is possible by using sonic crystals to vary the refractive index of two half-cylinders. The study has been carried out numerically, using the Finite Element Method. By changing the contrast of refractive indexes between the two half-cylinders or by rotating the Janus cylinder, acoustic hooks can be obtained that can be tunable with bending angle ranging from 1 degrees to 21 degrees. Full Width at Half-Maximum can be obtained with values close to the diffraction limit. This structure provides an efficient method to precisely tune the acoustic hook depending on it use.This work has been supported by Spanish Ministry of Science, Innovation and Universities (grant No. RTI2018-100792-B-I00). D.T.-S. acknowledges financial support from Ministerio de Ciencia, Innovacion y Universidades de Espana through grant BES-2016-077133.Castiñeira Ibáñez, S.; Tarrazó-Serrano, D.; Uris Martínez, A.; Rubio Michavila, C. (2021). Tunable acoustic hooks from Janus cylinder. Results in Physics. 24:1-5. https://doi.org/10.1016/j.rinp.2021.104134S152

Near-Field Light-Bending Photonic Switch: Physics of Switching Based on Three-Dimensional Poynting Vector Analysis

Photonic hook is a high-intensity, bent light focus with a proportional curvature to the wavelength of the incident light. Based on this unique light-bending phenomenon, a novel near-field photonic switch by means of a right-trapezoid dielectric Janus particle-lens embedded in the core of a planar waveguide is proposed for switching the photonic signals at two common optical communication wavelengths, 1310 nm and 1550 nm, by using numerical simulations. The signals at these two wavelengths can be guided to different routes according to their oppositely bent photonic hooks to realise wavelength selective switching. The switching mechanism is analysed by an in-house developed three-dimensional (3D) Poynting vector visualisation technology. It demonstrates that the 3D distribution and number of Poynting vector vortexes produced by the particle highly affect the shapes and bending directions of the photonic hooks causing the near-field switching, and multiple independent high-magnitude areas matched by the regional Poynting vector streamlines can form these photonic hooks. The corresponding mechanism can only be represented by 3D Poynting vector distributions and is being reported for the first time