Au-plasmon-assisted holographic azopolymer nano-cavity for wideband and low-threshold distributed feedback lasing

Optically pumped polymer nanolasers drive the development of integrated optoelectronic devices. Introduction of surface plasmon into nanolasers can effectively enhance the local electromagnetic field in the optical pumping processes. However, significant quenching effects on organic fluorescence emissions bring the challenge in high-efficient lasing from the distributed feedback (DFB) nano-device loaded with noble metal particles. In this Letter, we propose a non-contact localized field enhancement strategy between Au plasmon and optical gain layers for highly efficient and broadband DFB lasing. A tunable laser emission range from 618.5 nm to 642.5 nm is successfully achieved by adjusting the intersection angle in the holographic interference path. The lasing threshold in Au-plasmon-assisted holographic azopolymer nano-cavity structure is reduced by 33% from 0.912 mJ/cm² to 0.609 mJ/cm². The finite-difference time-domain results show that a strong electromagnetic field is built in the fluorescence-dye-filled waveguide structure. This work provides a perspective for the construction of nano-lasers with plasmonic amplification.