The Radiation of Two Dimension Dipole Oscillations in Subwavelength Hole Array

Smith-Purcell radiation is a kind of moving dipole oscillation radiation. In the subwavelength hole array, there are two-dimension dipole oscillations to happen when the e-beam is moving through the holes in a beam channel. It leads to the Smith-Purcell radiation energy enhanced, compared to one dipole oscillation in electron beam moving above period occurred metal surface. In addition, the dipole oscillation radiation takes place inside the hole, so the hole also plays a role to resonant the radiation so that the Smith-Purcell radiation has a good direction. Therefore, the radiation of two-dimension dipole oscillations in subwavelength hole array form a kind of Smith-Purcell radiation with intensity enhanced and the radiation direction tuned. It has potential to develop the vacuum electrons device based on Smith-Purcell radiation, such as Orotron, on-table THz free electron laser.