Jun 2010, Volume 3 Issue 2
    

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  • Research articles
    Yun-Feng XIAO, Yan LI, Qihuang GONG, Chang-Ling ZOU, Chun-Hua DONG, Zheng-Fu HAN,
    Asymmetric resonant cavities (ARCs) with smoothly deformed boundaries are currently under intensive study because they possess distinct properties that conventional symmetric cavities cannot provide. On one hand, it has been demonstrated that ARCs allow for highly directional emission instead of the in-plane isotropic light output in symmetric whispering-gallery cavities, such as microdisks, microspheres, and microtoroids. On the other hand, ARCs behave like open billiard system and thus offer an excellent platform to test classical and quantum chaos. This article reviews the recent progresses and prospects for the experimental realization of ARCs, with applications toward highly directional microlasing, strong-coupling light-matter interaction, and highly sensitive biosensing.
  • Research articles
    Guozhen SHEN, Di CHEN,
    One-dimensional (1-D) nanostructures have been the focus of current researches due to their unique physical properties and potential applications in nanoscale electronics and optoelectronics. They address and overcome the physical and economic limits of current microelectronic industry and will lead to reduced power consumption and largely increased device speed in next generation electronics and optoelectronics. This paper reviews the recent development on the device applications of 1-D nanostructures in electronics and optoelectronics. First, typical 1-D nanostructure forms, including nanorods, nanowires, nanotubes, nanobelts, and hetero-nanowires, synthesized from different methods are briefly discussed. Then, some nanoscale electronic and optoelectronic devices built on 1-D nanostructures are presented, including field-effect transistors (FETs), p-n diodes, ultraviolet (UV) detectors, light-emitting diodes (LEDs), nanolasers, integrated nanodevices, single nanowire solar cells, chemical sensors, biosensors, and nanogenerators. We then finalize the paper with some perspectives and outlook towards the fast-growing topics.
  • Research articles
    Ching-Ping WONG, Wei LIN, Ling-Bo ZHU, Hong-Jin JIANG, Rong-Wei ZHANG, Yi LI, Kyoung-Sik MOON,
    This paper addresses the state-of-the-art nano-science and technology regarding next generation high density microelectronics and photonics packaging applications, including carbon nanotubes (CNTs) for electrical/thermal devices, and molecular wires for electrical interconnects, etc.
  • Research articles
    Erich KASPER,
    On-chip optoelectronics allows the integration of optoelectronic functions with microelectronics. Recent advances in silicon substrate fabrication (silicon-on-insulator (SOI)) and in heterostructure engineering (SiGe/Si) push this field to compact (chipsize) waveguide systems with high-speed response (50-GHz subsystems realized, potential with above 100 GHz). In this paper, the application and requirements, the future solutions, the components and the physical effects are discussed.
    A very high refractive index contrast of the waveguide Si-core/SiO2-cladding is responsible for the submicron line widths and strong bendings realized in chipsize waveguide lines and passive devices. The SiGe/Si heterostructure shifts the accessible wavelength into infrared up to telecommunication wavelengths 1.30–1.55 µm. Germanium, although also an indirect semiconductor as silicon, offers direct optical transitions which are only 140 meV above the dominant indirect one. This is the basic property for realizing high-speed devices for future above 10 GHz on-chip clocks and, eventually, a laser source monolithically integrated on the Si substrate.
  • Research articles
    Avraham MAYEVSKY, Efrat BARBIRO-MICHAELY,
    Optical monitoring of tissue physiological and biochemical parameters in real-time is a new approach and a powerful tool for better clinical diagnosis and treatment. Most of the devices available for monitoring patients in critical conditions provide information on body respiratory and hemodynamic functions. Currently, monitoring of patients at the cellular and tissue level is very rare. Real-time monitoring of mitochondrial nicotinamide adenine dinucleotide (NADH) as an indicator of intra-cellular oxygen levels started 50 years ago. Mitochondrial dysfunction was recognized as a key element in the pathogenesis of various illnesses. We developed the “CritiView”
  • Research articles
    Xianzeng ZHANG, Shusen XIE, Zhenlin ZHAN, Haibin ZHAO, Jian GUO, Qing YE,
    The use of erbium,chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser with a wavelength of 2.78μm for hard bone tissue ablation was evaluated. The surface morphology and microstructure changes of bone tissue treated with Er,Cr:YSGG were analyzed as compared to those treated with diamond drill. The influence of fluence on ablation rate and ablation efficiency as well as microstructure was also examined. The results show that Er,Cr:YSGG laser can perform bone perforation that is more fine and presented a lot of unique advantages compared to traditional methods. An approximately linear relationship was observed between the ablation rate/ablation efficiency and radiant exposure. Increasing the radiant exposure irradiated on bone tissue will produce stronger thermal injury around the crater and result in microstructure changing.
  • Research articles
    Fan FAN, Kecheng YANG, Min XIA, Wei LI, Bo FU, Wei ZHANG,
    Although the use of blind deconvolution of image restoration is a widely known concept, little literatures have discussed in detail its application in the problem of restoration of underwater range-gated laser images. With the knowledge of the point spread function (PSF) and modulation transfer function (MTF) of water, underwater images can be better restored or enhanced. We first review image degradation process and Wells’ small angle approximation theory, and then provide an image enhancement method for our underwater laser imaging system by blind deconvolution method based on small angle approximation. We also introduce a modified normalized mean square error (NMSE) method to validate the convergence of the blind deconvolution algorithm which is applied in our approach. The results of different initial guess of blind deconvolution are compared and discussed. Moreover, restoration results are obtained and discussed by intentionally changing the MTF parameters and using non-model-based PSF as the initial guess.
  • Research articles
    Fei WANG, Xinliang ZHANG,
    We demonstrate a novel scheme to generate ultrawideband (UWB) monocycle and doublet pulses by inputting a dark return-to-zero (RZ) signal into a delay interferometer (DI), which accords with the general features in future applied UWB system, namely, single optical source input, simple configuration and passive device. The two polarized interferential beams have a time delay and a phase difference when they propagate through the DI. By adjusting polarization controllers (PCs), the total phase difference, i.e., the sum of the relative optical-phase difference between two orthogonally polarized components caused by PCs and the optical-phase shift due to birefringence of the polarization-maintaining fiber (PMF), the orientation angle of the polarization beam-splitter (PBS) relative to the two axes of the PMF are able to be changed and controlled. When the appropriate conditions are met, UWB monocycle and doublet pulses are generated conveniently.
  • Research articles
    Yueming ZHOU, Peixiang LU,
    Using the classical three-dimensional (3D) ensembles, we have investigated nonsequential double ionization (NSDI) of N2 by phase-stabilized few-cycle pulses. We find that the correlated electron momentum distributions in the direction parallel to the laser field strongly depend on the carrier-envelope phase (CEP) of few-cycle pulses, and this phase dependence is not affected by the alignment of the molecular axis relative to the laser field. Back analysis reveals that the ionization rate of the first electron and the recollision energy play a main role in the electron momentum distributions. Our results suggest that the few-cycle pulses with stabilized phase can serve as a powerful tool to investigate the recollision dynamics in NSDI of molecules.
  • Research articles
    Xubao WANG, Tiechuan ZUO,
    The research presented in this paper focuses on the laser-powder interaction. Through the experiment with metal powder in micrometers, we found that, in an invariable laser power density, the thickness of the final fabricated thin wall was similar to the geometrical dimension of the powder line, but could be much greater than the laser focus spot, even greater than two orders of magnitude. Furthermore, this paper showed that, the un-melted and semi-fused particles were concentrated. Thus, in this paper, combining the optical scattering theory with capillarity and infiltration theory pointed out the inducement effect of laser and the self-melting of powder. Based on the experimental phenomena and theory, we get our own ideas on the laser micro-fabrication.
  • Research articles
    Lei WANG, Yiwen ZHANG, Fei QIU, Zhimou XU, Yanli ZHAO, Yonglin YU, Ning ZHOU, Dingli WANG, Wen LIU,
    Gratings of distributed feedback laser diodes (DFB LDs) have been successfully manufactured by nanoimprint lithography (NIL). Uniform gratings with periods of about 240 nm and phase-shifted in the center have been fabricated by a soft press NIL employing a polymer stamp technology. Moreover, the shape of the grating is rectangle, rather than sinusoidal by holography. The test results show good characteristics of the electrical and spectral output. The results of this study indicate that NIL has high potential for the manufacture of DFB LDs.
  • Research articles
    Biao DONG, Hongwei SONG, Xue BAI, Yu WANG, Lin XU, Jiansheng CHEN, Lianxiang YU,
    In this paper, we present a room-temperature synthesis of silver dendrites in a poly(vinyl alcohol) (PVA)-Ag composite system with the assistance of high voltage. In the silver dendrites, the nanounits are platelike, thus the surface plasmon absorption bands of silver dendrites are tuned from visible to ~800nm, which is due to the template function of PVA and the assistance of high voltage. Scanning electron microscope (SEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDX) data confirm that the structures are crystalline silver embedded in PVA. The absorption results indicate that the ratio of PVA and Ag do not influence the position but the intensity of the near-infrared (NIR) absorption. This material has potential use in the field of bio-application and infrared sensors.
  • Research articles
    Zhihua YU, Fengguang LUO, Xu DI, Qing TAO, Weilin ZHOU, Bin LI, Liangjia ZONG, Guangjun WANG,
    A waveguide-based chip-to-chip optical interconnection network on printed circuit board (PCB) was designed and fabricated, and experiments confirmed that the data rate in each channel could reach above 3.125 Gbit/s and the bit error rate (BER) could be up to 1.27×10−18, which would be a good solution to solve the communication bottlenecks between high-speed very large scale integration chips. Besides, the whole design and fabrication of optical interconnection network on printed circuit board has the advantages of high reliable, low cost and ease of manufacture.