Design of an optical device with three functions based on coordinate transformation

Based on two-step coordinate transformation along the radial direction, an optical device with three functions is proposed. The proposed device functions as a transparent device, a vision-enabling internal cloak, and a movement-allowing external cloak. The general expressions of material parameters for the optical device are determined, and each function of the device is confirmed using full-wave simulation. The effect of material loss on device performance is also investigated. Future applications for the proposed device include antenna protection and military stealth.