Browsing by Author "Tseng, Ming Lun"

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Applications of plasmonic hotspots on laser-treated AgOx thin film
(2012)
Tseng, Ming Lun
;
Huang, Yao-Wei
;
Hsiao, Min-Kai
;
Huang, Hsin Wei
;
Lin, Yu-Hsuan
The femto-second-laser-treated AgOx thin film is used as the plasmon-active substrate for the applications of surface-enhanced Raman scattering (SERS), molecule sensing, and photocatalyst. The proposed technique is helpful for the solar energy harvest, green energy source, and biosensing with high efficiency and throughput.
Plasmon Inducing Effects for Enhanced Photoelectrochemical Water Splitting: X-ray Absorption Approach to Electronic Structures
(2012-08-01)
Chen, Hao Ming
;
Chen, Chih Kai
;
Chen, Chih-Jung
;
Cheng, Liang-Chien
;
Wu, Pin Chieh
Artificial photosynthesis using semiconductors has been investigated for more than three decades for the purpose of transferring solar energy into chemical fuels. Numerous studies have revealed that the introduction of plasmonic materials into photochemical reaction can substantially enhance the photo response to the solar splitting of water. Until recently, few systematic studies have provided clear evidence concerning how plasmon excitation and which factor dominates the solar splitting of water in photovoltaic devices. This work demonstrates the effects of plasmons upon an Au nanostructure-ZnO nanorods array as a photoanode. Several strategies have been successfully adopted to reveal the mutually independent contributions of various plasmonic effects under solar irradiation. These have clarified that the coupling of hot electrons that are formed by plasmons and the electromagnetic field can effectively increase the probability of a photochemical reaction in the splitting of water. These findings support a new approach to investigating localized plasmon-induced effects and charge separation in photoelectrochemical processes, and solar water splitting was used herein as platform to explore mechanisms of enhancement of surface plasmon resonance.
Stress-Induced 3D Chiral Fractal Metasurface for Enhanced and Stabilized Broadband Near-Field Optical Chirality
(2019-08-01)
Tseng, Ming Lun
;
Lin, Zhan-Hong
;
Kuo, Hsin Yu
;
Huang, Tzu-Ting
;
Huang, Yi-Teng
Metasurfaces comprising 3D chiral structures have shown great potential in chiroptical applications such as chiral optical components and sensing. So far, the main challenges lie in the nanofabrication and the limited operational bandwidth. Homogeneous and localized broadband near-field optical chirality enhancement has not been achieved. Here, an effective nanofabrication method to create a 3D chiral metasurface with far- and near-field broadband chiroptical properties is demonstrated. A focused ion beam is used to cut and stretch nanowires into 3D Archimedean spirals from stacked films. The 3D Archimedean spiral is a self-similar chiral fractal structure sensitive to the chirality of light. The spiral exhibits far- and near-field broadband chiroptical responses from 2 to 8 mu m. With circularly polarized light (CPL), the spiral shows superior far-field transmission dissymmetry and handedness-dependent near-field localization. With linearly polarized excitation, homogeneous and highly enhanced broadband near-field optical chirality is generated at a stably localized position inside the spiral. The effective yet straightforward fabrication strategy allows easy fabrication of 3D chiral structures with superior broadband far-field chiroptical response as well as strongly enhanced and stably localized broadband near-field optical chirality. The reported method and chiral metasurface may find applications in broadband chiral optics and chiral sensing.