Abstract:
Nanoporous honeycomb membranes on InP (111) surfaces emit ultrafast coherent terahertz pulses under near-infrared optical excitation. Irradiating the membranes with heavy noble gas Kr or Xe ions enhances the terahertz emission. The emission does not vary with in-plane magnetic field rotation and exhibits three-cycle dependence on azimuthal-angle rotation. Both suggest the terahertz source is not transient currents but opticalrectification enhanced by the heavy-ion irradiation.