Measuring the Invisible

Daniele Abate

Stefano Longhi

Reflectionless defects in Hermitian tight-binding lattices, synthesized by the intertwining operator technique of supersymmetric quantum mechanics, are generally not invisible and time-of-flight measurements could reveal the existence of the defects. Here it is shown that, in a certain class of non-Hermitian tight-binding lattices with complex hopping amplitudes, defects in the lattice can appear fully invisible to an outside observer. The synthesized non-Hermitian lattices with invisible defects possess a real-valued energy spectrum; however, they lack parity-time ($\mathcal{PT}$) symmetry, which does not play any role in the present work.

Luis Romero Cortés, Reza Maram, José Azaña

We introduce a new concept for broadband invisibility, enabling the first experimental demonstration of phase-preserving cloaking, undetectable by coherent spectral and temporal measurements. The concept is demonstrated by concealing a filter in a fiber-optics system.

NAPOLEON CAMUS M. HERMOSO

Zhiqiang Chen