Lianghui Chen
Chinese Academy of Sciences
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Publication
Featured researches published by Lianghui Chen.
Applied Physics Letters | 2007
Qiaoqiang Gan; Baoshan Guo; Guofeng Song; Lianghui Chen; Zhan Fu; Yujie J. Ding; Filbert J. Bartoli
The authors present an analysis of a plasmonic surface-wave splitter, simulated using a two-dimensional finite-difference time-domain technique. A single subwavelength slit is employed as a high-intensity nanoscale excitation source for plasmonic surface waves, resulting in a miniaturized light-surface plasmon coupler. With different surface structures located on the two sides of the slit, the device is able to confine and guide light waves of different wavelengths in opposite directions. Within the 15 mu m simulation region, it is found that the intensity of the guided light at the interface is roughly two to eight times the peak intensity of the incident light, and the propagation length can reach approximately 42 and 16 mu m and at the wavelengths of 0.63 and 1.33 mu m, respectively. (c) 2007 American Institute of Physics.
Optics Express | 2009
Wanhua Zheng; Mingxin Xing; Gang Ren; Steven G. Johnson; Wenjun Zhou; Wei Chen; Lianghui Chen
In this work, we present the design of an integrated photonic-crystal polarization beam splitter (PC-PBS) and a low-loss photonic-crystal 60 degrees waveguide bend. Firstly, the modal properties of the PC-PBS and the mechanism of the low-loss waveguide bend are investigated by the two-dimensional finite-difference time-domain (FDTD) method, and then the integration of the two devices is studied. It shows that, although the individual devices perform well separately, the performance of the integrated circuit is poor due to the multi-mode property of the PC-PBS. By introducing deformed airhole structures, a single-mode PC-PBS is proposed, which significantly enhance the performance of the circuit with the extinction ratios remaining above 20 dB for both transverse-electric (TE) and transverse-magnetic (TM) polarizations. Both the specific result and the general idea of integration design are promising in the photonic crystal integrated circuits in the future.
Applied Physics Letters | 2007
Baoshan Guo; Guofeng Song; Lianghui Chen
The fabrication of plasmonic very-small-aperture lasers is demonstrated in this letter. It is an integration of the surface plasmon structures and very-small-aperture lasers (VSAL). The experimental and numerical results demonstrate that the transmission field can be confined to a spot with subwavelength width in the far field, and the power output can be enhanced 140% of the normal VSAL. Such a device can be useful in the application of a high resolution far-field scanning optical microscope.
Journal of Photonics for Energy | 2011
Wenli Bai; Qiaoqiang Gan; Guofeng Song; Lianghui Chen; Zakya H. Kafafi; Filbert J. Bartoli
Absorption enhancement by a double plasmonic nanostructure in molecular organic photovoltaics (OPVs) is theoretically investigated. The structure consists of a periodic array of metal nanodiscs on one side of the OPV active layers and a thin metal nanohole array on the other side. Excitation of coupled modes of localized surface plasmon polaritons at the nanodiscs and short-range surface plasmon polaritons at the nanohole array causes the electromagnetic field to be highly concentrated within the organic active layers, leading to a polarization-independent, broadband absorption enhancement in the visible and near-infrared portion of the solar spectrum. Calculations show that an optimized double plasmonic structure can enhance the total photon absorption by >125% for molecular OPVs based on a double heterojunction of an electron donor/hole transporter and an electron acceptor/transporter.
Journal of Lightwave Technology | 2008
Gang Ren; Wanhua Zheng; Yejin Zhang; Ke Wang; Xiaoyu Du; Mingxin Xing; Lianghui Chen
The guided modes of a two-dimensional photonic crystal straight waveguide and a waveguide bend are studied in order to find the high transmission mechanism for the waveguide bend. We find that high transmission occurs when the mode patterns and wave numbers match, while the single-mode condition in the waveguide bend is not necessarily required. According to the mechanism, a simply modified bend structure with broad high transmission band is proposed. The bandwidth is significantly increased from 19 to 116 nm with transmission above 90%, and covers the entire C band of optical communication.
IEEE Transactions on Nanotechnology | 2009
Baoshan Guo; Guofeng Song; Lianghui Chen
The authors present an analysis of plasmonic wave filter and curved waveguide, simulated using a 2-D finite-difference time-domain technique. With different dielectric materials or surface structures located on the interface of the metal/dielectric, the resonant enhanced wave filter can divide light waves of different wavelengths and guide them with low losses. And the straight or curved waveguide can confine and guide light waves in a subwavelength scale. Within the 20 mum simulation region, it is found that the intensity of the guided light at the interface is roughly four times the peak intensity of the incident light.
Journal of Lightwave Technology | 2007
Baoshan Guo; Qiaoqiang Gan; Guofeng Song; Jianxia Gao; Lianghui Chen
In this paper, we analyze light transmission through a single subwavelength slit surrounded by periodic grooves in layered films consisting of Au and dielectric material. A subwavelength grating is scanned numerically by the finite difference time domain method in two dimensions. The results show that the transmission field can be confined to a spot with subwavelength width in the far field and can be useful in the application of a high-resolution far-field scanning optical microscope
Applied Physics Letters | 2006
Qiaoqiang Gan; Guofeng Song; Guohua Yang; Yun Xu; Jianxia Gao; Yuzhang Li; Qing Cao; Lianghui Chen; Haiwei Lu; Zhonghao Chen; Wei Zeng; Rongjin Yan
A near-field scanning optical microscopy (NSOM) system employing a very-small-aperture laser (VSAL) as an active probe is reported in this Letter. The VSAL in our experiment has an aperture size of 300nm×300nm and a near-field spot size of about 600nm. The resolution of the NSOM system with the VSAL can reach about 600nm, and even 400nm. Considering the high output power of the VSAL, such a NSOM system is a potentially useful tool for nanodetection, data storage, nanolithography, and nanobiology.
Optics Letters | 2005
Qiaoqiang Gan; Guofeng Song; Yun Xu; Jianxia Gao; Qing Cao; Xuejian Pan; Yuan Zhong; Guohua Yang; Xiaopeng Zhu; Lianghui Chen
The fabrication of very-small-aperture lasers is demonstrated, and their performance is analyzed. Because of strong optical feedback caused by a gold film on the front facet of the laser, its behavior changes: The threshold current decreases, the density of light inside the laser diode and the redshift effect of the spectra are enhanced, and the laser diodes lifetime is shorter than that of common laser diodes with large driving current.
Applied Physics Letters | 2011
Yang Wei; Wenquan Ma; Jianliang Huang; Yanhua Zhang; Yongheng Huo; Kai Cui; Lianghui Chen; Yanli Shi
We report a modified dots-in-a-well (DWELL) infrared photodetector by inserting some very thin GaAs or AlGaAs layers into the InAs dots. The photoluminescence (PL) measurements indicate that the modified DWELL structure with the insertion layers (ILs) of GaAs has a larger peak intensity and a narrower PL linewidth than that without the ILs. For the modified DWELL detector with AlGaAs ILs, the peak detection wavelength reaches very long infrared window of 14.1 μm. The peak detectivity D∗ is 1.1×108 cm Hz1/2/W at 77 K under normal incidence infrared irradiation.