Low-Threshold Surface Plasmon Lasing using the Band Edge Mode in a Bi-Periodic Groove Array

We study surface plasmon lasing based on periodic and bi-periodic groove arrays etched on a silver substrate. It is interesting to find that the bi-periodic structure can open a clear band gap of surface plasmon polaritons near the first Brillouin zone boundary, and thus it is promising to utilize the band edge modes of surface plasmon polaritons. A low threshold for the surface plasmon lasing effect is demonstrated numerically, owing to the low group velocity of the band edge mode, which provides a feasible way to design surface plasmon lasers.