Abstract
We propose a kind of indefinite media at infrared frequency without artificial structures. Natural existing indefinite media are realized based on strong anisotropy in polar lattice vibrations in different directions, parallel or perpendicular to the crystal axis. As an example, the dielectric dispersions of α-Al2O3 single crystal with different polarizations of electric field are measured, the regions of indefinite permittivity are demonstrated and an all-angle negative refraction is also shown based on the simulated results. This mechanism to realize indefinite medium will supply a promising way to explore natural existing negative refraction materials.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
