Integration of Nanoscale Light Emitters and Hyperbolic Metamaterials: An Efficient Platform for the Enhancement of Random Laser Action*

Hyperbolic metamaterials (HMM) have emerged as novel materials with exciting functionalities, especially for optoelectronic devices. Here, we provide the first attempt to integrate hyperbolic metamaterials with light emitting nanostructures, which enables to strongly enhance random laser action with reduced lasing threshold. Interestingly, compared with the reference sample based on Si substrate, the HMM sample achieves 6.2 times lasing intensity, lowers 20.7% of lasing threshold, shortens 44% lifetime, and enhances the differential quantum efficiency by 4.5 times. The underlying mechanism can be interpreted well based on the fact that the high-k modes excited by hyperbolic metamaterials can greatly increase the possibility of forming close loops decreasing the energy consumption for the propagation of scattered photons in the matrix. Moreover, rough interface between ZnO nanoparticles and the HMM can assist the propagation of the out-coupling power of the high-k modes to the far-field easily rather than let the emitted light get trapped inside the multilayer structure.