Enhanced radiation using Cerenkov effect in Fano metamerical

The Fano metamaterial provides a way of trapping and releasing electromagnetic waves in microwave and terahertz regime. We show that, by utilizing the electromagnetic properties, the efficiency of radiation power from the Cerenkov effect in our recently proposed metallic metamaterial is much larger than the one from the ordinary Cerenkov and Smith-Purcell effects. The optimization of the efficiency was numerically conducted by manipulating the quality(Q) factor of the trapped Cerenkov light. The proposed metamaterial is suitable for developing compact and highly efficient free electron lasers.