Researchers at Shanghai Jiao Tong University and the National Center for Nanoscience and Technology developed a method to electrically break polariton symmetry through non-Hermitian dissipation engineering, Nature Materials reported on September 7, 2026.
The team layered alpha-molybdenum trioxide flakes directly onto aligned carbon nanotubes. In this heterostructure, the nanotube array acts as an anisotropic dissipative medium. Overdamped carrier dynamics preclude conventional polariton hybridization, creating proximity-induced resistive coupling instead. The nanotube layer operates as a tunable momentum-space loss filter, selectively attenuating polariton propagation along specific crystallographic directions.
Electrostatic gating regulates the Drude loss inside the carbon nanotube layer. Applying gate voltages from 200 V to -150 V produces continuous, reversible transitions in polariton topology, reshaping symmetric hyperbolic contours into asymmetric shear wavefronts. Unlike standard refractive-index engineering methods that require strict wavevector matching, this dissipative approach shapes wave topologies without coherent hybridization.
Near-field measurements confirmed the effect across optical frequencies spanning 870 to 900 inverse centimeters. The researchers tracked polariton wavefront shearing across crystal-to-nanotube twist angles of 0°, 25°, 42°, 70°, and 90°. For the voltage-tuning demonstrations, the team set the alpha-molybdenum trioxide crystal axis at a 39-degree angle relative to the carbon nanotube axis using a 95-nanometer-thick flake illuminated at 896 inverse centimeters.
