title: Cooperative Enhancement of Second-Harmonic Generation from a Single CdS Nanobelt-Hybrid Plasmonic Structure.
abstract: Semiconductor nanostructures (e.g., nanowires and nanobelts) hold great promise as subwavelength coherent light sources, nonlinear optical frequency converters, and all-optical signal processors for optoelectronic applications. However, at such small scales, optical second-harmonic generation (SHG) is generally inefficient. Herein, we report on a straightforward strategy using a thin Au layer to enhance the SHG from a single CdS nanobelt by 3 orders of magnitude. Through detailed experimental and theoretical analysis, we validate that the augmented SHG originates from the mutual intensification of the local fields induced by the plasmonic nanocavity and by the reflections within the CdS Fabry-Pérot resonant cavity in this hybrid semiconductor-metal system. Polarization-dependent SHG measurements can be employed to determine and distinguish the contributions of SH signals from the CdS nanobelt and gold film, respectively. When the thickness of gold film becomes comparable to the skin depth, SHG from the gold film can be clearly observed. Our work demonstrates a facile approach for tuning the nonlinear optical properties of mesoscopic, nanostructured, and layered semiconductor materials.
authors.affiliation: †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371.
authors.forename: Xinfeng
authors.initials: X
authors.lastname: Liu
authors.affiliation: †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371.
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.
authors.forename: Wee Kiang
authors.initials: WK
authors.lastname: Chong
authors.affiliation: †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371.
authors.forename: Jing Ngei
authors.initials: JN
authors.lastname: Yip
authors.affiliation: †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371.
authors.forename: Xinglin
authors.initials: X
authors.lastname: Wen
authors.affiliation: †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371.
authors.forename: Zhenpeng
authors.initials: Z
authors.lastname: Li
authors.affiliation: ‡Energy Research Institute@NTU (ERI@N), Nanyang Technological University, 50 Nanyang Drive, Singapore 637553.
authors.forename: Fengxia
authors.initials: F
authors.lastname: Wei
authors.affiliation: †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371.
authors.forename: Guannan
authors.initials: G
authors.lastname: Yu
authors.affiliation: †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371.|§NOVITAS, Nanoelectronics Center of Excellence, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798.
authors.forename: Qihua
authors.initials: Q
authors.lastname: Xiong
authors.affiliation: †Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371.|‡Energy Research Institute@NTU (ERI@N), Nanyang Technological University, 50 Nanyang Drive, Singapore 637553.
authors.forename: Tze Chien
authors.initials: TC
authors.lastname: Sum
keywords: CdS nanobelt; Fabry−Pérot resonance; SHG enhancement; nonlinear optics; plasmonic nanocavity; plasmons; second-harmonic generation