A multi-wavelength SPASER based on plasmonic tetramer cavity

Surface plasmon (SP) amplification by stimulated emission of radiation (SPASER) as nanoscale coherent light source has great applications in biomedical sensing, imaging, optical communications, and ultrafast spectroscopy. Shrinking coherent light sources to subwavelength regions can provide new insight into light-matter interactions. In this theoretical work, we utilize a multi-resonance plasmonic substrate as a cavity to design a multi-wavelength SPASER. The plasmonic substrate consists of four crisscrossed.sub-elements with symmetric disposition, the tetramer can support multiple plasmonic resonance modes. With the appropriate gain layer, the different SPs modes can be stimulated, and SPASER with different wavelengths can be obtained.