Excitation of Ultraslow High‐q Surface Plasmon Polariton Modes in Dense Arrays of Double‐Walled Carbon Nanotubes

This work explores the plasmonic properties of parallel double‐walled carbon nanotube arrays. It is shown that ultraslow surface plasmon polariton (SPP) modes possessing a phase velocity some orders of magnitude lower than the speed of light in vacuum and high Q ‐factor can be generated in such arrays. It is demonstrated that nonrelativistic electron beams with the velocity less than 10 6 m s −1 can be used to excite SPPs in arrays of double‐walled carbon nanotubes. For the SPP modes excited by an electron beam, the frequency range of SPP waves and electron beam velocities corresponding to the phase matching within a wide frequency range are determined. It opens the way to design slow‐wave structures based on the dense arrays of multiwalled carbon nanotubes employing an efficient energy transfer from the pump to the SPPs.