Distortion-free conductivity-dependent temporal cloak based on tunnelling chiral medium

Abstract

Complex conductivity-dependent birefringent undistorted pulses propagation and development of time cloak are investigated. The left and right circularly polarized (LCP/RCP) beams refractive indices, absorptions, dispersion and intensity distribution are controlled and modified with complex conductivity and tunnelling effect in a chiral medium. Sixteen types of waves and corresponding absorption coefficients and refractive indices are investigated. The corresponding dispersions of LCP/RCP beams fluctuated with complex conductivity and tunnelling frequency significantly modified the time cloak. The manipulation of dispersion with significant enhancement of refractive index has direct relation with time gap or hole for temporal cloaking devices. A time gap of $$8\,\mu s-10\,\mu s$$ has been calculated between the LCP/RCP beams with forward current. Furthermore, the time gap of $$5 \mu s$$ is reported in each LCP/RCP beams with backward current. The pulses propagation in conductive medium is the superposition of sixteen types of waves in the medium and any external event $$E_E (t)$$ when interacting with the transmitting pulse $$E^{R,L}(\sigma ,t)$$ in this time hole interval, the result is $$E_E(t)E^{R,L}(\sigma ,t)=0$$ and the information will be undetectable to the outside hackers. These theoretical results may be more helpful to the sensitivity of information detection and noise-free secure communications.