Experimental Demonstration of Luneburg Waveguides

Abstract

Transformation optics gives rise to numerous unusual optical devices, such as novel metamaterial lenses and invisibility cloaks. Very recently Mattheakis et al. [1] have suggested theoretical design of an optical waveguide based on a network of Luneburg lenses, which may be useful in sensing and nonlinear optics applications. Here we report the first experimental realization of such Luneburg waveguides. We have studied wavelength and polarization dependent performance of the waveguides. Explosive development of elecromagnetic metamaterials and transformation optics (TO) produced such novel and fascinating optical devices as perfect lenses [2], hyperlenses [3-5], invisibility cloaks [6-9], and perfect absorbers [10]. Very recently Mattheakis et al. [1] have suggested a theoretical design of an optical waveguide based on a network of TO-based lenses, such as a Luneburg lens [11], and suggested that such a waveguide may be useful in sensing and nonlinear optics applications. Here we report the first experimental realization of such Luneburg waveguides, which operate in the visible

Three‐dimensional Luneburg lens at optical frequencies

“…With the development of modern lithography technology, two‐dimensional (2D) Luneburg lenses have been demonstrated in a silicon‐based waveguide, leading to the promising application in chip integrated photonic circuits . In addition, 2D Luneburg lenses based on the polymer waveguide structures provide an effective approach to focus and guide the surface plasmon polaritons with reduced absorption and low loss , indicating the high potential in sensing and enhanced nonlinear processes. However, it is difficult to implement a truly 3D Luneburg lens at optical frequencies with usual GRIN medium due to the large index contrast along the radius and the precisely control requirement for the GRIN distribution .…”

Structural Luneburg lens for broadband cloaking and wave guiding

“…The same process is repeated after the wave passes the third and fourth SLLs, producing a circular wavefront at the exit of the four SLLs without much loss. There is an analogy between the structural wave guiding properties of the SLLs and the optical Luneburg waveguides reported in the literature 60 , 61 . Therefore, the four (or any other even numbers above 4) SLLs can serve as a waveguide for structural waves.…”

3D-Printing for Transformation Optics in Electromagnetic High-Frequency Lens Applications

“…This tool allows to transform any electromagnetic device into a different equivalent, having the same electromagnetic characteristics but with a different morphology. This has been the kickoff of many interesting applications [3][4][5], specially in electromagnetic high-frequency topologies [6,7]. One of the main applications of this tool is oriented to improve lens designs, such as simplifying their geometry and reducing their overall size [8][9][10].…”