Wenqi Zhu, Shawn M. Divitt, Matthew S. Davis, Cheng Zhang, Ting Xu, Henri J. Lezec, Amit K. Agrawal
Recent advancements in the ability to design, fabricate and characterize optical and optoelectronic devices at the nanometer scale have led to tremendous developments in the miniaturization of optical systems and circuits. Development of wavelength scale optical elements that are able to efficiently generate, manipulate and detect light, and their subsequent integration, has been the main focus of ongoing research in this area. To achieve coherent light generation at the nanoscale, much of the research over the last few decades has focused on achieving lasing using high-index dielectric resonators under the form of photonic- crystals or whispering gallery mode resonators. More recently, nanolasers based on metallic resonators that sustain surface plasmons, collective electron oscillations at the interface between a metal and a dielectric, have emerged as a promising candidate. In this article, we describe the fundamentals of surface plasmons, and the various embodiments of plasmon resonators that serve as the building block for plasmon lasers. Based on these concepts, we discuss the various experimental implementations of plasmon lasers, highlight the characteristic parameters that describe their performance and finally discuss some of their potential applications.