Browsing by Author "Su, Chen-Wei"

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Broadband gold nanoantennas arrays with transverse dimension effects
(2016-08-08)
Su, Chen-Wei
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Chen, Kuo-Ping
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光電系統研究所
;
影像與生醫光電研究所
;
Institute of Photonic System
Broadband resonance in gold paired-rods nanoantennas and paired-strips gratings is investigated when the nanostructure's transverse (non-polarization) dimension is changed from paired-rods to paired-strips. Increasing the transverse dimension blue shifts the resonance wavelength and widens its bandwidth due to cancellation of the magnetic field between nanoantennas. A derived resistor-inductor-capacitor (RLC) equivalent circuit model verifies the nanostructures' resonance when elongating the transverse dimensions. Paired-strips gratings have a bandwidth 2.04 times that of paired-rods nanoantennas. (C) 2016 Optical Society of America
Electrically active nanoantenna array enabled by varying the molecular orientation of an interfaced liquid crystal
(2016-01-01)
Hsiao, Yu-Cheng
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Su, Chen-Wei
;
Yang, Zong-Han
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Cheypesh, Yevheniia I.
;
Yang, Jhen-Hong
A system comprising a gold nanoantenna array covered with a high-birefringence liquid crystal (LC) material is introduced. By applying voltage across the LC bulk, we demonstrate that the refractive-index and polarization changes significantly modify the hybrid plasmonic-photonic resonances in the system. The hybrid structure enables the active control of the spectrum as well as a large shift in resonance wavelength of the metallic nanoantennas by means of an externally applied electric field. Our modeling supports the observed results, by assuming that the nanoantenna array leads to two orthogonal easy axes with a finite anchoring energy. In combination of the nanostructured surface with birefringent LC, tunability up to 90 nm is achieved in the visible wavelengths, opening the door towards nanoscale displays or nano-optical switches.
Optimization of effective absorption enhancement of paired-strips gold nanoantennas arrays in organic thin-films
(2018-01-01)
Yang, Zih-Ying
;
Su, Chen-Wei
;
Chen, Kuo-Ping
;
光電系統研究所
;
影像與生醫光電研究所
This study sought to optimize the dimensional characteristics of paired-strips gold nanoantennas embedded in a P3HT:PCBM thin-film by taking into account the tradeoff between the size of the nanostructures and absorber layer as well as the gaps between nanoparticles, to maximize the effective absorption enhancement. The average enhancement behavior within the working region was discussed using integral analysis, which is important for overall enhancement. The discussion would focus on comparing the bands' features of paired-strips nanoantennas embedded in a dielectric thin-film, and in air. By the average absorption 3D slices plots, in which the dimension width, height, and gap are changed with a fixed wavelength; the optimized dimension of paired-strips nanoantennas could be realized. Fixing the period (400 nm) of paired-strips nanoantennas embedded in P3HT:PCBM thin-films (120 nm in thickness) enhanced absorption by 9.8 times.