Browsing by Author "Raja, Soniya S."

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Broadband Multifunctional Plasmonic Logic Gates
(2018-07-04)
Sang, Yungang
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Wu, Xiaojia
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Raja, Soniya S.
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Wang, Chun-Yuan
;
Li, Haozhi
Plasmonic logic gates provide a promising platform to realize diffraction-unlimited all-optical logic circuits. However, previous plasmonic logic gates suffer from narrow bandwidth and high loss. Here, broadband plasmonic logic gates are proposed and demonstrated using a unique design based on curved silver gratings. These logic gates can maintain a high intensity contrast ratio (29 dB) under front optical illumination. And, the broadband feature is achieved due to the feature of zero optical path difference from different positions of the curved grating to the output port. All the seven fundamental logic gates are demonstrated. In addition, different types of logic gates can be realized using the same device configuration. The possibility of multifunctionality makes these logic gates easy for device fabrication and system integration.
Monolayer Semiconductor Surface-Emitting Lasers Using 2D Dark Plasmonic Cavities
(2018-01-01)
Wang, Chun-Yuan
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Shi, Jinwei
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Raja, Soniya S.
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Chen, Chun-An
;
Zhang, Xin-Quan
We demonstrated a low-threshold lasing from a monolayer gain medium which is made possible due to 2D feedback mechanism via strong exciton-SPP coupling in both real space and a wide range of momentum space.
Plasmonic enhancement and control of optical nonlinearity in monolayer WS2
(2018-01-01)
Liang, Wei-Yun
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Ahn, Hyeyoung
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Sang, Yungang
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Wang, Yanrong
;
Shi, Jinwei
A giant SHG enhancement is achieved from monolayer-WS2 incorporated onto 2D plasmonic metasurfaces (Ag-nanogroove-grating) in resonance with the excitonic resonance of monolayer-WS2. An optical encoding technique is demonstrated based on plasmonic manipulation of SHG polarization.
Plasmonic Enhancement and Manipulation of Optical Nonlinearity in Monolayer Tungsten Disulfide
(2018-10-01)
Shi, Jinwei
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Liang, Wei-Yun
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Raja, Soniya S.
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Sang, Yungang
;
Zhang, Xin-Quan
Monolayer transition metal dichalcogenides (TMDCs) have large second-order optical nonlinearity owing to broken inversion symmetry in two-dimensional (2D) crystals. However, despite the strong light-matter coupling in monolayer TMDCs, their nonlinear responses are ultimately limited by subnanometer thickness. Here, a dramatic enhancement of the second-harmonic generation (SHG) is achieved from monolayer tungsten disulfide (WS2) incorporated onto a 2D silver (Ag) nanogroove grating with subwavelength pitch. By tuning surface plasmon mode and second-harmonic frequency in resonance with the C exciton in WS2, a large SHG enhancement factor (approximate to 400) and a large conversion efficiency (approximate to 2.0 x 10(-5)) can be obtained. Furthermore, the azimuthal angle dependence of polarized SHG from monolayer WS2 can be manipulated by the nanogroove plasmonic mode. Based on this property, a polarization-modulated optical encoding technique is demonstrated. The results suggest that 2D TMDC-plasmonic hybrid metasurface structures can provide an ideal integration platform for on-chip nonlinear photonics and plasmonics.