Ultrathin planar waveguide equipment and design method thereof

Abstract

The invention relates to elastic fluctuation in engineering structures, in particular to ultrathin planar waveguide equipment and a design method thereof.The waveguide equipment comprises a flat plateand a waveguide structure arranged on the flat plate, the waveguide structure is composed of two layers of metasurfaces with sub-wavelength thicknesses, and each metasurface is composed of periodically-arranged supercells, wherein each super cell comprises unit cells with two gradient indexes, the transmissivity t of each unit cell is not less than 0.9, the width of each unit cell is H, the phasechanges of the elastic waves passing through the two unit cells are pi and 2pi respectively, the phase gradient of the super surface is L = 2H, L represents the width of the super cell, and lambda / L> 2 must be met in order to make the elastic waves incident on the super surface, wherein lambda represents the wavelength. By designing the waveguide equipment in any shape, the purpose that elasticwaves are propagated along an expected path can be achieved, and the waveguide equipment has the advantages of being light and thin in structure, small in size, wide in working frequency band, high indesignability and the like.

Description

technical field [0001] The invention relates to elastic fluctuations in engineering structures, in particular to an ultra-thin planar waveguide device and a design method thereof. Background technique [0002] In 1842, Swiss physicist Daniel Colladon used water to guide light. In his experiment, light was completely internally reflected at the interface between water and air, and the water flow made the light travel along this trajectory in the form of a parabola. This phenomenon is called "fountain of light". This experiment is actually the earliest realization of a modern optical waveguide device. The use of two materials with different refractive indices can achieve complete reflection of light at the interface, and typical applications include optical fibers and optical cavities. Optical fiber is mainly composed of two parts, core and cladding. The core has a higher refractive index than the cladding. When the light is incident on the cladding and the incident angle ...

AI Technical Summary

Problems solved by technology

If two materials are used to realize the complete reflection of the elastic wave at the interface, this not only limits the direction of the incident wave, but also is not convenient for processing and manufacturing, so it is not an ideal slab waveguide device

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