title: A room temperature low-threshold ultraviolet plasmonic nanolaser.
abstract: Constrained by large ohmic and radiation losses, plasmonic nanolasers operated at visible regime are usually achieved either with a high threshold (10(2)-10(4) MW cm(-2)) or at cryogenic temperatures (4-120 K). Particularly, the bending-back effect of surface plasmon (SP) dispersion at high energy makes the SP lasing below 450 nm more challenging. Here we demonstrate the first strong room temperature ultraviolet (~370 nm) SP polariton laser with an extremely low threshold (~3.5 MW cm(-2)). We find that a closed-contact planar semiconductor-insulator-metal interface greatly lessens the scattering loss, and more importantly, efficiently promotes the exciton-SP energy transfer thus furnishes adequate optical gain to compensate the loss. An excitation polarization-dependent lasing action is observed and interpreted with a microscopic energy-transfer process from excitons to SPs. Our work advances the fundamental understanding of hybrid plasmonic waveguide laser and provides a solution of realizing room temperature UV nanolasers for biological applications and information technologies.
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
authors.forename: Guangyuan
authors.initials: G
authors.lastname: Li
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
authors.forename: Xinfeng
authors.initials: X
authors.lastname: Liu
authors.affiliation: Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
authors.forename: Fang
authors.initials: F
authors.lastname: Qian
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA.
authors.forename: Yat
authors.initials: Y
authors.lastname: Li
authors.affiliation: 1] Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore [2] Singapore-Berkeley Research Initiative for Sustainable Energy, 1 Create Way, Singapore 138602, Singapore.
authors.forename: Tze Chien
authors.initials: TC
authors.lastname: Sum
authors.affiliation: Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Charles M
authors.initials: CM
authors.lastname: Lieber
authors.affiliation: 1] Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore [2] NOVITAS, Nanoelectronics Centre of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Qihua
authors.initials: Q
authors.lastname: Xiong