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179 results on '"Zhang, Ruohu"'

37. Ultra Sharp Fano Resonances Induced by Coupling between Plasmonic Stub and Circular Cavity Resonators

Author

Hu Guohua, Yun Binfeng, Cui Yi-Ping, and Zhang Ruohu

Subjects
Materials science, business.industry, Surface plasmon, Biophysics, Physics::Optics, Fano resonance, 02 engineering and technology, 021001 nanoscience & nanotechnology, Slow light, 01 natural sciences, Biochemistry, Stub (electronics), 010309 optics, Resonator, Optics, 0103 physical sciences, Figure of merit, Optoelectronics, 0210 nano-technology, business, Refractive index, Plasmon, Biotechnology
Abstract

A plasmonic waveguide system composed of metal-insulator-metal (MIM) stub coupled with circular cavity resonator was proposed to produce ultra sharp Fano resonances, which resulted from the coupling between the ultra narrow discrete resonances and the ultra broad spectrum of the plasmonic circular cavity and stub resonator, respectively. The spectral line shapes of the Fano resonances can be easily adjusted by changing the structure parameters. And the transmittance of the system can sharply decrease from peak (“on state”) to valley (“off state”) with wavelength shifts of only about 8 nm. Due to the sharp phase change of the ultra asymmetric Fano resonance, a maximum group index of about 180 can be realized. Also, the ultra sharp spectrum contributes to a highly efficient plasmonic refractive index sensor, which can yield a linear sensitivity of 1277 nm/RIU and figure of merit of about 2.1 × 104. The proposed structure may have potential applications in nanoscale filter, slow light, and refractive index sensor.

Published
2016

38. Low cost polymer sampled waveguide Bragg grating fabricated by using contact lithography

Author

Cui Yi-Ping, Zhou Juan, Yun Binfeng, Zhang Ruohu, and Hu Guohua

Subjects
chemistry.chemical_classification, PHOSFOS, Materials science, business.industry, Physics::Optics, Polymer, Cladding (fiber optics), Atomic and Molecular Physics, and Optics, Spectral line, Computer Science::Other, Electronic, Optical and Magnetic Materials, Wavelength, Optics, Fiber Bragg grating, chemistry, Optoelectronics, Electrical and Electronic Engineering, Physical and Theoretical Chemistry, Reactive-ion etching, business, Nonlinear Sciences::Pattern Formation and Solitons, Lithography
Abstract

A low cost polymer sampled waveguide Bragg grating which can be fabricated by using the simple contact lithography is proposed. By using the contact lithography and reactive ion etching, the sampled Bragg grating structures were fabricated on the waveguide bottom cladding, where a channel waveguide was fabricated on top of it as the waveguide core to form the polymer sampled waveguide Bragg grating working at around 1550 nm. The measured transmission and reflection spectra of the fabricated polymer sampled waveguide Bragg grating exhibit multiple dips and peaks, respectively. And the wavelength interval among the peaks is 0.376 nm, which shows good agreement with the theoretical predictions.

Published
2015

39. Fractional-Order Differentiator Using Silicon-Based Cascaded Dual Micro-Rings

Author

李静 Li Jing, 胡国华 Hu Guohua, 恽斌峰 Yun Binfeng, 张若虎 Zhang Ruohu, and 陈梦 Chen Meng

Subjects
Physics, Differentiator, Order (ring theory), Electrical and Electronic Engineering, Topology, Atomic and Molecular Physics, and Optics, Dual (category theory), Silicon based
Published
2020

40. Reconfigurable Microwave Photonic Bandpass Filter Based on Silicon Nitride Microring and Carrier Separation

Author

洪红 Hong Hong, 恽斌峰 Yun Binfeng, 张若虎 Zhang Ruohu, 徐雪朦 Xu Xuemeng, 李静 Li Jing, 杨惠敏 Yang Huimin, and 郑鹏飞 Zheng Pengfei

Subjects
chemistry.chemical_compound, Materials science, Silicon nitride, chemistry, Band-pass filter, business.industry, Separation (aeronautics), Optoelectronics, Electrical and Electronic Engineering, business, Atomic and Molecular Physics, and Optics, Microwave photonics
Published
2020

49. Ultra-Compact On-chip Electro-Optic Waveguide Ring Resonators Based on Asymmetric Au-(Pb, La)(Zr, Ti)O3-Au Structure

Author

Cui Yi-Ping, Hu Guohua, Yun Binfeng, Qi Zhipeng, and Zhang Ruohu

Subjects
Fabrication, Materials science, Extinction ratio, business.industry, Surface plasmon, Biophysics, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Biochemistry, law.invention, 010309 optics, Resonator, Wavelength, law, 0103 physical sciences, Optoelectronics, Insertion loss, Thin film, 0210 nano-technology, business, Waveguide, Biotechnology
Abstract

Waveguide ring resonators (WRRs) operating at a telecom window of 1.4∼1.6 μm based on asymmetric Au-(Pb, La)(Zr, Ti)O3-Au structure is proposed and investigated. Electro-optical control of such WRRs is conducted by introducing epitaxial (Pb, La)(Zr, Ti)O3 (PLZT) thin films as the core layer deposited between the upper and lower gold slabs with different widths. The long-term reliability, large electro-optic (EO) coefficients, and spontaneous polarization properties of PLZT thin films have ensured high performance of our WRRs. It has been demonstrated that the footprint of WRR can be fabricated less than 20 μm2 with the radius of ring resonator around 1 μm through combining PLZT thin films with surface plasmons (SPs). Furthermore, the large extinction ratio (∼43 dB), as well as comparatively low insertion loss (

Published
2015

50. Silicon-assisted surface enhanced fluorescence toward improved assay performances.

Author

Zhang, Ruohu, Lu, Hui, Zong, Shenfei, Lu, Changgui, Yun, Binfeng, Hu, Guohua, Zhu, Li, and Cui, Yiping

Subjects
*FLUORESCENCE, *GOLD nanoparticles, *ELECTRIC fields, *SILVER nanoparticles, *ROSE bengal, *NANOSILICON
Abstract

A novel scheme of silicon-assisted surface enhanced fluorescence (SEF) is presented for SEF-based assays, where the blank signal suppression and the fluorescence signal enhancement is combined. The P-doped, (100) oriented silicon substrate is used to quench the fluorescence of Rose Bengal (RB) molecules attached to it, resulting in an effectively suppressed background signal, which is useful for a lower limit of detection (LOD). When a proper quantity of silver nanoparticles (AgNPs) is deposited on the RB-attached silicon substrate, a significant fluorescence enhancement of up to around 290 fold is obtained, which helps to improve the sensitivity in fluorescence-based assays. Besides, conventional gold nanoparticles (AuNPs) have also been demonstrated to exhibit excellent SEF effect using the presented scheme, providing improved stability and biocompatibility. The mechanism of the observed SEF effect has been investigated, and both the decreased apparent quantum yield and the silicon-induced electric field redistribution are considered to play important roles. The experimental results suggest that the presented scheme holds great potential in the SEF-based assays aiming at higher sensitivity and lower LOD. [ABSTRACT FROM AUTHOR]

Published
2021
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