A review of recent progress in plasmon-assisted nanophotonic devices

Plasmonics squeezes light into dimensions far beyond the diffraction limit by coupling the light with the surface collective oscillation of free electrons at the interface of a metal and a dielectric. Plasmonics, referred to as a promising candidate for high-speed and high- density integrated circuits, bridges microscale photonics and nanoscale electronics and offers similar speed of photonic devices and similar dimension of electronic devices. Various types of passive and active surface plasmon polariton （SPP） enabled devices with enhanced deep-subwavelength mode confinement have attracted increasing interest including waveguides, lasers and biosensors. Despite the trade-off between the unavoidable metal absorption loss and extreme light concentration, the ever-increasing research efforts have been devoted to seeking low-loss plasmon-assisted nanophotonic devices with deep-subwavelength mode confinement, which might find potential applications in high-density nanophotonic integration and efficient nonlinear signal processing. In addition, other plasmon-assisted nanophotonic devices might also promote grooming functionalities and applica- tions benefiting from plasmonics. In this review article, we give a brief overview of our recent progress in plasmon-assisted nanophotonic devices and their wide applications, including long-range hybrid plasmonic slot （LRHPS） waveguide, ultra-compact plasmonic microresonator with efficient thermo-optic tuning, high quality （Q） factor and small mode volume, compact active hybrid plasmonic ring resonator for deep-subwave- length lasing applications, fabricated hybrid plasmonic waveguides for terabit-scale photonic interconnection, and metamaterials-based broadband and selective generation of orbital angular momentum （OAM） carrying vector beams. It is believed that plasmonics opens possible new ways to facilitate next chip-scale key devices and frontier technologies.