Ultrafast Terahertz Dynamics in Hybrid Van der Waals Superconductor‐Topological Insulator Metamaterials

Hybrid van der Waals heterostructures that combine topological insulators with high‐temperature superconductors offer a promising platform for tunable terahertz (THz) photonics compatible with cryogenic quantum technologies. We present a theoretical and numerical study of ultrafast THz modulation in proximitized (Bi 2‐ x In x )Se 3 interfaced with Bi 2 Sr 2 CaCu 2 O 8+ δ . Indium‐driven topological phase transitions enable selective control of THz transmission, yielding a tuning depth of 23.8% and a resonance shift of 111 GHz. Under ultrafast optical excitation, the hybrid system reaches a modulation depth of 30.4%, a frequency shift of 52 GHz, and a group delay of 0.71 ps. These results provide a design framework for topological–superconducting metamaterials and indicate their potential for dynamic THz control in quantum photonic architectures.