Browsing by Author "Lin, Meng-Hsien"

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Plasmonic Green Nanolaser Based on a Metal-Oxide-Semiconductor Structure
(2011-10-01)
Wu, Chen-Ying
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Kuo, Cheng-Tai
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Wang, Chun-Yuan
;
He, Chieh-Lun
;
Lin, Meng-Hsien
Realization of smaller and faster coherent light sources is critically important for the emerging applications in nanophotonics and information technology. Semiconductor lasers are arguably the most suitable candidate for such purposes. However, the minimum size of conventional semiconductor lasers utilizing dielectric optical cavities for sustaining laser oscillation is ultimately governed by the diffraction limit (similar to(lambda/2n)(3) for three-dimensional (3D) cavities, where lambda is the free-space wavelength and n is the refractive index). Here, we demonstrate the 3D subdiffraction-limited laser operation in the green spectral region based on a metal oxide semiconductor (MOS) structure, comprising a bundle of green-emitting InGaN/GaN nanorods strongly coupled to a gold plate through a SiO(2) dielectric nanogap layer. In this plasmonic nanocavity structure, the analogue of MOS-type "nanocapacitor" in nanoelectronics leads to the confinement of the plasmonic field into a 3D mode volume of 8.0 x 10(-4) mu m(3) (similar to 0.14(lambda/2n)(3)).
Plasmonic Metasurfaces for Nonlinear Optics and Quantitative SERS
(2016-08)
Gwo, Shangjr
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Wang, Chun-Yuan
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Chen, Hung-Ying
;
Lin, Meng-Hsien
;
Sun, Liuyang
Plasmonic metasurfaces consist of two-dimensional arrays of metallic nanoresonators (plasmonic "meta-atoms"), which exhibit collective and tunable resonance properties controlled by electromagnetic near-field coupling. These man-made surfaces can produce a range of unique optical properties unattainable with natural materials. In this review, we focus on the emerging applications of metasurfaces with precisely engineered plasmonic properties for nonlinear optics and surface-enhanced Raman spectroscopy (SERS). In practice, these applications are quite susceptible to material losses and structural imperfections, such as variations in size, shape, periodicity of meta-atoms, and their material states (crystallinity, impurity, and oxidation, etc.). In these aspects, conventional top-down lithographic techniques are facing major challenges due to inherent limitations in intrinsic material properties and material quality introduced during growth, synthesis, and fabrication processes, as well as achievable lithographic resolution. Moreover, they are prohibitively expensive and time-consuming for fabrication over large areas. Here, we show that colloidal silver crystals (millimeter-sized single-crystalline plates and thiolate-capped nanoparticles) synthesized by solution-based chemical methods are excellent material platforms for the fabrication of high-quality plasmonic metasurfaces. In, particular, both top-down (focused ion-beam milling) and bottom-up (centimeter-scale self-assembly) techniques can be exploited to generate uniform and precisely engineered colloidal metasurfaces for broadband tunable (across the full visible range) second-harmonic generation and quantitative SERS at the single-molecule level.
Ultracompact Pseudowedge Plasmonic Lasers and Laser Arrays
(2018-02-01)
Chou, Yu-Hsun
;
Hong, Kuo-Bin
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Chang, Chun-Tse
;
Chang, Tsu-Chi
;
Huang, Zhen-Ting
Concentrating light at the deep subwavelength scale by utilizing plasmonic effects has been reported in various optoelectronic devices with intriguing phenomena and functionality. Plasmonic waveguides with a planar structure exhibit a two-dimensional degree of freedom for the surface plasmon; the degree of freedom can be further reduced by utilizing metallic nanostructures or nanoparticles for surface plasmon resonance. Reduction leads to different lightwave confinement capabilities, which can be utilized to construct plasmonic nanolaser cavities. However, most theoretical and experimental research efforts have focused on planar surface plasmon polariton (SPP) nanolasers. In this study, we combined nanometallic structures intersecting with ZnO nanowires and realized the first laser emission based on pseudowedge SPP waveguides. Relative to current plasmonic nanolasers, the pseudowedge plasmonic lasers reported in our study exhibit extremely small mode volumes, high group indices, high spontaneous emission factors, and high Purell factors beneficial for the strong interaction between light and matter. Furthermore, we demonstrated that compact plasmonic laser arrays can be constructed, which could benefit integrated plasmonic circuits.