title: Surface roughness effects on aluminium-based ultraviolet plasmonic nanolasers.
abstract: We systematically investigate the effects of surface roughness on the characteristics of ultraviolet zinc oxide plasmonic nanolasers fabricated on aluminium films with two different degrees of surface roughness. We demonstrate that the effective dielectric functions of aluminium interfaces with distinct roughness can be analysed from reflectivity measurements. By considering the scattering losses, including Rayleigh scattering, electron scattering, and grain boundary scattering, we adopt the modified Drude-Lorentz model to describe the scattering effect caused by surface roughness and obtain the effective dielectric functions of different Al samples. The sample with higher surface roughness induces more electron scattering and light scattering for SPP modes, leading to a higher threshold gain for the plasmonic nanolaser. By considering the pumping efficiency, our theoretical analysis shows that diminishing the detrimental optical losses caused by the roughness of the metallic interface could effectively lower (~33.1%) the pumping threshold of the plasmonic nanolasers, which is consistent with the experimental results.
authors.affiliation: National Taiwan Ocean University, Department of Mechanical and Mechatronic Engineering, Keelung 202, Taiwan.
authors.forename: Yi-Cheng
authors.initials: YC
authors.lastname: Chung
authors.affiliation: Academia Sinica, Research Center for Applied Sciences, Taipei 115, Taiwan.
authors.forename: Pi-Ju
authors.initials: PJ
authors.lastname: Cheng
authors.affiliation: National Chiao Tung University, Institute of Lighting and Energy Photonics, Tainan 711, Taiwan.|National Chiao Tung University, Department of Photonics, Hsinchu 300, Taiwan.
authors.forename: Yu-Hsun
authors.initials: YH
authors.lastname: Chou
authors.affiliation: National Chiao Tung University, Department of Electronics Engineering, Hsinchu 300, Taiwan.
authors.forename: Bo-Tsun
authors.initials: BT
authors.lastname: Chou
authors.affiliation: National Chiao Tung University, Department of Photonics, Hsinchu 300, Taiwan.
authors.forename: Kuo-Bin
authors.initials: KB
authors.lastname: Hong
authors.affiliation: National Taiwan Ocean University, Department of Mechanical and Mechatronic Engineering, Keelung 202, Taiwan.
authors.forename: Jheng-Hong
authors.initials: JH
authors.lastname: Shih
authors.affiliation: National Chiao Tung University, Department of Electronics Engineering, Hsinchu 300, Taiwan.
authors.forename: Sheng-Di
authors.initials: SD
authors.lastname: Lin
authors.affiliation: National Chiao Tung University, Department of Photonics, Hsinchu 300, Taiwan.
authors.forename: Tien-Chang
authors.initials: TC
authors.lastname: Lu
authors.affiliation: National Taiwan Ocean University, Department of Mechanical and Mechatronic Engineering, Keelung 202, Taiwan.|National Taiwan Ocean University, Institute of Optoelectronic Sciences, Keelung 202, Taiwan.
authors.forename: Tzy-Rong
authors.initials: TR
authors.lastname: Lin