Self-focusing and the Talbot effect in conformal transformation optics

TL;DR

This paper demonstrates a conformal transformation optics device that exhibits self-focusing and Talbot effects, bridging geometric and wave optics, with potential applications in digital information transfer.

Contribution

It introduces a gradient-index micro-structured waveguide implementing CTO, showing combined geometric and wave optical phenomena in a feasible experimental setup.

Findings

Demonstrated self-focusing in CTO device

Observed Talbot effect in the system

Potential for digital information transfer without diffraction

Abstract

Transformation optics (TO) has been used to propose various novel optical devices. With the help of metamaterials, several intriguing designs, such as invisibility cloaks, have been implemented. However, as the basic units should be much smaller than the working wavelengths to achieve the effective material parameters, and the sizes of devices should be much larger than the wavelengths of illumination to work within the light-ray approximation, it is a big challenge to implement an experimental system that works simultaneously for both geometric optics and wave optics. In this letter, by using a gradient-index micro-structured optical waveguide, we realize a device of conformal transformation optics (CTO) and demonstrate its self-focusing property for geometry optics and Talbot effect for wave optics. In addition, the Talbot effect in such a system has a potential application to transfer digital information without diffraction. Our findings demonstrate the photon controlling ability of CTO in a feasible experiment system.