Nanoscale active hybrid plasmonic laser with a metal-clad metal-insulator-semiconductor square resonator

We investigate a nanoscale active hybrid plasmonic laser with a metal-clad metal-insulator-semiconductor (MIS) square resonator. By forming a metal layer surrounding the MIS structure, the cavity mode can be well bound to the ultrasmall volume in the spacer region atop a semiconductor nanosquare, and the cavity Q factor can be statically tuned by changing the spacer height and has little influence on the wafer bonding substrate. Numerical simulations for an optimized structure show that the cavity feedback has been significantly improved due to the near-zero radiative loss and low metal loss. Abundant direct-gap InGaN gain material and low threshold gain make this structure a promising platform for nanolaser operating at room temperature. A four-level two-electron finite-difference time-domain simulation shows that this cavity can achieve room-temperature lasing at visible wavelengths with an estimated optical pump threshold of 190 mu W, and the active material gain of InGaN should reach 0.855 mu m(-1). (C) 2014 Optical Society of Americ