Moving Janus dipoles and preservation of face-selective coupling

Determine whether a uniformly moving Janus dipole can preserve darkness at its non-coupling face or instead exhibit controlled leakage that enables new functionalities under motion.

Background

Static Janus dipoles have been studied extensively and experimentally realized at microwave and optical frequencies, where their near-field behavior is characterized by face-selective coupling: one face couples strongly to an evanescent or guided mode, while the opposite face is effectively non-coupling. Section 4.1 considers how uniform relativistic motion could alter this behavior through velocity-induced phase gradients and Doppler shifts.

The authors specifically identify as unresolved whether motion preserves complete suppression at the non-coupling face or produces a controllable leakage of coupling. Resolving this question would clarify the dynamical limits of Janus directionality and could enable frequency-multiplexed or otherwise motion-controlled near-field coupling.