| Record 1 of 13 |
| Author(s): Zhao, WF (Zhao, W. F.); Hou, W (Hou, W.); Guo, L (Guo, L.); Li, G (Li, G.); Lin, XC (Lin, X. C.); Li, JM (Li, J. M.) |
| Title: 12 W high efficiency single frequency ring laser |
| Source: LASER PHYSICS LETTERS, 7 (3): 210-212 MAR 2010 |
Abstract: Single-frequency output power of 12 W at 1064 nm is demonstrated. Pumped by a fiber-coupled diode laser, the Nd:YVO4 produces 58.6% of the slope efficiency with respect to absorbed pump power, and 52.7% of the optical-optical efficiency and nearly diffraction-limited output with a beam quality parameter of M-2 approximate to 1.11. To the best of our knowledge, this is the highest slope efficiency and optical-optical efficiency in single-frequency Nd:YVO4 ring laser. The slope efficiency of the single frequency laser is close to the limit of the efficiency.
[GRAPHICS]
output spectrum of the single-frequency Nd:YVO4 ring laser (C) 2010 by Astro Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA |
| ISSN: 1612-2011 |
| DOI: 10.1002/lapl.200910136 |
| Record 2 of 13 |
| Author(s): Liu, AJ (Liu, A. J.); Chen, W (Chen, W.); Qu, HW (Qu, H. W.); Jiang, B (Jiang, B.); Zhou, WJ (Zhou, W. J.); Xing, MX (Xing, M. X.); Zheng, WH (Zheng, W. H.) |
| Title: Single-mode holey vertical-cavity surface-emitting laser with ultra-narrow beam divergence |
| Source: LASER PHYSICS LETTERS, 7 (3): 213-217 MAR 2010 |
Abstract: We demonstrated oxide-confined 850-nm vertical-cavity surface-emitting lasers (VCSELs) with a two-dimensional petal-shaped holey structure composed of several annular-sector-shaped holes. Four types of devices with different hole numbers were designed and fabricated. The measured results showed that the larger hole number was beneficial to purifying the lasing mode, and realizing the single-mode operation. The side mode suppression ratio (SMSR) exceeded 30 dB throughout the entire drive current. Mode selective loss mechanism was used to explain the single-mode characteristic. The single-mode devices possessed good beam profiles, and the lowest divergence angle was as narrow as 3.2 degrees (full width at half maximum), attributed to the graded index profile and the shallow etching in the top distributed Bragg reflector (DBR).
[GRAPHICS]
Scanning electron microscope (SEM) image of the fabricated device (C) 2010 by Astro Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA |
| ISSN: 1612-2011 |
| DOI: 10.1002/lapl.200910130 |
| Record 3 of 13 |
| Author(s): Liu, Y (Liu, Yan); Xu, XJ (Xu, Xuejun); Xing, B (Xing, Bo); Yu, YD (Yu, Yude); Yu, JZ (Yu, Jinzhong) |
| Title: Fabrication of a Low-Loss SSC Using High-Dose Electron Beam Lithography Exposure With Negative PMMA Resist |
| Source: IEEE PHOTONICS TECHNOLOGY LETTERS, 22 (7): 501-503 APR 1 2010 |
| Abstract: A silicon-on-insulator optical fiber-to-waveguide spot-size converter (SSC) using Poly-MethylMethAcrylate (PMMA) is presented for integrated optical circuits. Unlike the conventional use of PMMA as a positive resist, it has been successfully used as a negative resist with high-dose electron exposure for the fabrication of ultrafine silicon wire waveguides. Additionally, this process is able to reduce the side-wall roughness, and substantially depresses the unwanted propagation loss. Exploiting this technology, the authors demonstrated that the SSC can improve coupling efficiency by as much as over 2.5 dB per coupling facet, compared with that of SSC fabricated with PMMA as a positive resist with the same dimension. |
| ISSN: 1041-1135 |
| DOI: 10.1109/LPT.2010.2040998 |
| Record 4 of 13 |
| Author(s): Ji, HM (Ji Hai-Ming); Yang, T (Yang Tao); Cao, YL (Cao Yu-Lian); Xu, PF (Xu Peng-Fei); Gu, YX (Gu Yong-Xian); Liu, Y (Liu Yu); Xie, L (Xie Liang); Wang, ZG (Wang Zhan-Guo) |
| Title: A 10 Gb/s Directly-Modulated 1.3 mu m InAs/GaAs Quantum-Dot Laser |
| Source: CHINESE PHYSICS LETTERS, 27 (3): Art. No. 034209 MAR 2010 |
| Abstract: We demonstrate 10 Gb/s directly-modulated 1.3 mu m InAs quantum-dot (QD) lasers grown on GaAs substrates by molecular beam epitaxy. The active region of the QD lasers consists of five-stacked InAs QD layers. Ridge-waveguide lasers with a ridge width of 4 mu m and a cavity length of 600 mu m are fabricated with standard lithography and wet etching techniques. It is found that the lasers emit at 1293 nm with a very low threshold current of 5 mA at room temperature. Furthermore, clear eye-opening patterns under 10 Gb/s modulation rate at temperatures of up to 50 degrees C are achieved by the QD lasers. The results presented here have important implications for realizing low-cost, low-power-consumption, and high-speed light sources for next-generation communication systems. |
| ISSN: 0256-307X |
| Article Number: 034209 |
| DOI: 10.1088/0256-307X/27/3/034209 |
| Record 5 of 13 |
| Author(s): Wang, H (Wang Hui); Liang, H (Liang Hu); Wang, Y (Wang Yong); Ng, KW (Ng Kar-Wei); Deng, DM (Deng Dong-Mei); Lau, KM (Lau Kei-May) |
| Title: Effects of AlGaN/AlN Stacked Interlayers on GaN Growth on Si (111) |
| Source: CHINESE PHYSICS LETTERS, 27 (3): Art. No. 038103 MAR 2010 |
| Abstract: We report the growth of high quality and crack-free GaN film on Si (111) substrate using Al0.2Ga0.8N/AlN stacked interlayers. Compared with the previously used single AlN interlayer, the AlGaN/AlN stacked interlayers can more effectively reduce the tensile stress inside the GaN layer. The cross-sectional TEM image reveals the bending and annihilation of threading dislocations (TDs) in the overgrown GaN film which leads to a decrease of TD density. |
| ISSN: 0256-307X |
| Article Number: 038103 |
| DOI: 10.1088/0256-307X/27/3/038103 |
| Record 6 of 13 |
| Author(s): Kong, N (Kong Ning); Liu, JQ (Liu Jun-Qi); Li, L (Li Lu); Liu, FQ (Liu Feng-Qi); Wang, LJ (Wang Li-Jun); Wang, ZG (Wang Zhan-Guo) |
| Title: Strain-Compensated InGaAs/InAlAs Quantum Cascade Detector of 4.5 mu m Operating at Room Temperature |
| Source: CHINESE PHYSICS LETTERS, 27 (3): Art. No. 038501 MAR 2010 |
| Abstract: We present a strain-compensated InP-based InGaAs/InAlAs photovoltaic quantum cascade detector grown by solid source molecular beam epitaxy. The detector is based on a vertical intersubband transition and electron transfer on a cascade of quantum levels which is designed to provide longitudinal optical phonon extraction stairs. By careful structure design and growth, the whole epilayer has a residual strain toward InP substrate of only -2.8 x 10(-4). A clear narrow band detection spectrum centered at 4.5 mu m has been observed above room temperature for a device with 200 x 200 mu m(2) square mesa. |
| ISSN: 0256-307X |
| Article Number: 038501 |
| DOI: 10.1088/0256-307X/27/3/038501 |
| Record 7 of 13 |
| Author(s): Zhu, B (Zhu Bin); Han, Q (Han Qin); Yang, XH (Yang Xiao-Hong); Ni, HQ (Ni Hai-Qiao); He, JF (He Ji-Fang); Niu, ZC (Niu Zhi-Chuan); Wang, X (Wang Xin); Wang, XP (Wang Xiu-Ping); Wang, J (Wang Jie) |
| Title: Metamorphic InGaAs p-i-n Photodetectors with 1.75 mu m Cut-Off Wavelength Grown on GaAs |
| Source: CHINESE PHYSICS LETTERS, 27 (3): Art. No. 038504 MAR 2010 |
| Abstract: Top-illuminated metamorphic InGaAs p-i-n photodetectors (PDs) with 50% cut-off wavelength of 1.75 mu m at room temperature are fabricated on GaAs substrates. The PDs are grown by a solid-source molecular beam epitaxy system. The large lattice mismatch strain is accommodated by growth of a linearly graded buffer layer to create a high quality virtual InP substrate indium content in the metamorphic buffer layer linearly changes from 2% to 60%. The dark current densities are typically 5 x 10(-6) A/cm(2) at 0 V bias and 2.24 x 10(-4) A/cm(2) at a reverse bias of 5 V. At a wavelength of 1.55 mu m, the PDs have an optical responsivity of 0.48 A/W, a linear photoresponse up to 5 mW optical power at -4 V bias. The measured -3 dB bandwidth of a 32 mu m diameter device is 7 GHz. This work proves that InGaAs buffer layers grown by solid source MBE are promising candidates for GaAs-based long wavelength devices. |
| ISSN: 0256-307X |
| Article Number: 038504 |
| DOI: 10.1088/0256-307X/27/3/038504 |
| Record 8 of 13 |
| Author(s): Shiratori, Y (Shiratori, Yuta); Miura, K (Miura, Kensuke); Jia, R (Jia, Rui); Wu, NJ (Wu, Nan-Jian); Kasai, S (Kasai, Seiya) |
| Title: Compact Reconfigurable Binary-Decision-Diagram Logic Circuit on a GaAs Nanowire Network |
| Source: APPLIED PHYSICS EXPRESS, 3 (2): Art. No. 025002 2010 |
| Abstract: We describe a reconfigurable binary-decision-diagram logic circuit based on Shannon's expansion of Boolean logic function and its graphical representation on a semiconductor nanowire network. The circuit is reconfigured by using programmable switches that electrically connect and disconnect a small number of branches. This circuit has a compact structure with a small number of devices compared with the conventional look-up table architecture. A variable Boolean logic circuit was fabricated on an etched GaAs nanowire network having hexagonal topology with Schottky wrap gates and SiN-based programmable switches, and its correct logic operation together with dynamic reconfiguration was demonstrated. (C) 2010 The Japan Society of Applied Physics DOI: 10.1143/APEX.3.025002 |
| ISSN: 1882-0778 |
| Article Number: 025002 |
| DOI: 10.1143/APEX.3.025002 |
| Record 9 of 13 |
| Author(s): Wang, ZG (Wang, Z. G.); Li, JB (Li, J. B.); Gao, F (Gao, F.); Weber, WJ (Weber, W. J.) |
| Title: Tensile and compressive mechanical behavior of twinned silicon carbide nanowires |
| Source: ACTA MATERIALIA, 58 (6): 1963-1971 APR 2010 |
| Abstract: Molecular dynamics simulations with the Tersoff potential were used to study the response of twinned SiC nanowires under tensile and compressive strain. The critical strain of the twinned nanowires can be enhanced by twin stacking faults, and their critical strains are larger than those of perfect nanowires with the same diameters. Under axial tensile strain, the bonds of the nanowires are stretched just before failure. The failure behavior is found to depend on the twin segment thickness and the diameter of the nanowires. An atomic chain is observed for thin nanowires with small twin segment thickness under tension strain. Under axial compressive strain, the collapse of twinned SiC nanowires exhibits two different failure modes, depending on the length and diameter of the nanowires, i.e., shell buckling for short nanowires and columnar buckling for longer nanowires. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. |
| ISSN: 1359-6454 |
| DOI: 10.1016/j.actamat.2009.11.039 |
| Record 10 of 13 |
| Author(s): Gan, QQ (Gan, Qiaoqiang); Gao, YK (Gao, Yongkang); Wang, Q (Wang, Qing); Zhu, L (Zhu, Lin); Bartoli, F (Bartoli, Filbert) |
| Title: Surface plasmon waves generated by nanogrooves through spectral interference |
| Source: PHYSICAL REVIEW B, 81 (8): Art. No. 085443 FEB 2010 |
| Abstract: A pure surface plasmon polariton (SPP) model predicted that the SPP excitation in a slit-groove structure at metallodielectric interfaces exhibits an intricate dependence on the groove width P. Lalanne et al. [Phys. Rev. Lett. 95, 263902 (2005); Nat. Phys. 2, 551 (2006)]. In this paper, we present a simple far-field experiment to test and validate this interesting theoretical prediction. The measurement results clearly demonstrate the predicted functional dependence of the SPP coupling efficiency on groove width, in good agreement with the SPP picture. |
| ISSN: 1098-0121 |
| Article Number: 085443 |
| DOI: 10.1103/PhysRevB.81.085443 |
| Record 11 of 13 |
| Author(s): Zhu, L (Zhu, Lin); Chen, HF (Chen, Haifeng); Zhang, X (Zhang, Xu); Guo, K (Guo, Kai); Wang, SJ (Wang, Shujing); Wang, Y (Wang, Yu); Pei, WH (Pei, Weihua); Chen, HD (Chen, Hongda) |
| Editor(s): Shi, R; Fu, WJ; Wang, YQ; Wang, HB |
| Title: Design of Portable Multi-Channel EEG Signal Acquisition System |
| Source: PROCEEDINGS OF THE 2009 2ND INTERNATIONAL CONFERENCE ON BIOMEDICAL ENGINEERING AND INFORMATICS, VOLS 1-4: 180-183 2009 |
| Conference Title: 2nd International Conference on Biomedical Engineering and Informatics |
| Conference Date: OCT 17-19, 2009 |
| Conference Location: Tianjin, PEOPLES R CHINA |
| Conference Host: Tianjin Univ Technol |
| Abstract: A portable multi-channel electroencephalography (EEG) signal acquisition system operated by battery is designed in this paper. EEG is a recording of the electrical activity of the brain from the scalp and the recorded waveforms provide insights into the dynamic aspects of brain activity. The amplifier with a bandwidth of 0.8-35Hz is designed by use of integrated circuits such as the low-power instrumentation amplifier AD623, low-power, high gain operational amplifiers TLC27L4, etc. The amplified EEG signals are digitized by an A/D (analog to digital) converter built-in MSP 430 MCU (micro-controller unit). The digitized signals are transmitted to a PC by a wired serial port or stored in the SD (secure digital) memory card. Experimental results show that the system could implement the acquisition and storage of the EEG signals efficiently. This system would be of benefit to all involved in the use of EEG for clinical diagnosis and monitoring, or even BCI (brain computer interface). |
| ISBN: 978-1-4244-4133-4 |
| Record 12 of 13 |
| Author(s): Guo, Y (Guo, Y.); Liu, XL (Liu, X. L.); Song, HP (Song, H. P.); Yang, AL (Yang, A. L.); Xu, XQ (Xu, X. Q.); Zheng, GL (Zheng, G. L.); Wei, HY (Wei, H. Y.); Yang, SY (Yang, S. Y.); Zhu, QS (Zhu, Q. S.); Wang, ZG (Wang, Z. G.) |
| Title: A study of indium incorporation in In-rich InGaN grown by MOVPE |
| Source: APPLIED SURFACE SCIENCE, 256 (10): 3352-3356 MAR 1 2010 |
| Abstract: InGaN/GaN heterostructures have been deposited onto (0 0 0 1) sapphire by our home-made low pressure MOVPE with different growth parameters. It has been noted that the indium incorporation depends by a complex way on a number of factors. In this work, the effect of substrate temperature, trimethylindium input flow and V/III ratio on the indium incorporation has been investigated. Finally, by optimizing the growth parameters, we made a series of single-phase InGaN samples with indium content from 10% up to 45%. (C) 2009 Elsevier B.V. All rights reserved. |
| ISSN: 0169-4332 |
| DOI: 10.1016/j.apsusc.2009.11.081 |
| Record 13 of 13 |
| Author(s): Lu, GJ (Lu Guo-Jun); Zhu, JJ (Zhu Jian-Jun); Jiang, DS (Jiang De-Sheng); Wang, YT (Wang Yu-Tian); Zhao, DG (Zhao De-Gang); Liu, ZS (Liu Zong-Shun); Zhang, SM (Zhang Shu-Ming); Yang, H (Yang Hui) |
| Title: Structural and optical properties of Al1-xInxN epilayers on GaN template grown by metalorganic chemical vapor deposition |
| Source: CHINESE PHYSICS B, 19 (2): Art. No. 026804 FEB 2010 |
| Abstract: This paper reports that Al1-xInxN epilayers were grown on GaN template by metalorganic chemical vapor deposition with an In content of 7%-20%. X-ray diffraction results indicate that all these Al1-xInxN epilayers have a relatively low density of threading dislocations. Rutherford backscattering/channeling measurements provide the exact compositional information and show that a gradual variation in composition of the Al1-xInxN epilayer happens along the growth direction. The experimental results of optical reflection clearly show the bandgap energies of Al1-xInxN epilayers. A bowing parameter of 6.5 eV is obtained from the compositional dependence of the energy gap. The cathodoluminescence peak energy of the Al1-xInxN epilayer is much lower than its bandgap, indicating a relatively large Stokes shift in the Al1-xInxN sample. |
| ISSN: 1674-1056 |
| Article Number: 026804 |
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