Recent Progress in Low Threshold Plasmonic Nanolasers

Plasmonic nanolasers as a new class of coherent laser beyond the diffraction limit have attracted a lot of attention. However, the ultrahigh optical confinement caused by the plasmon effect is inevitably accompanied by metal absorption loss, thus increasing the pump threshold of the plasmonic nanolaser. In the past decade, many good results about low threshold plasmonic nanolasers have been realized and successfully extended to various applications. Here, this advance is discussed and some opinions are offered. First, based on the theoretical model and key parameters of the plasmonic nanolaser, the factors affecting the threshold are analyzed. Subsequently, the experimental efforts on the realization of low threshold plasmonic nanolasers from optical pumping to electrical pumping are reviewed. Their applications in on-chip optical interconnects, biochemical analysis, and far-field structure are then considered. Finally, feasible approaches to threshold reduction are discussed, as well as more possible applications in the future.