掺CdSxSe1-x玻璃波导分布反馈光学双稳器件

本文给出了掺CdS_xSe_1-x玻璃平面波导分布反馈(DFB)光学双稳器件的设计和制备方法,实现了低功耗、快速的本征光学双稳。     

Growth and optical property of ZnWO4: Er crystal

Good quality crystals ZnWO₄ activated with Er³⁺ have been grown by means of Czochralski method and characterized using optical spectroscopy techniques. XRD, absorption spectra, fluorescence spectrum are presented and the Judd-Ofelt intensity parameters Ω₂, Ω₄, and Ω₆ are obtained to be 6.76×10^-20, 0.37×10^-20, and 0.50×10^-20 cm², respectively. Along crystallographic axes, refractive indices are presented. The fluorescence decay time of the ⁴I_13/2 level has also been investigated and shows an exponential behavior with a lifetime value of 5.52 ms. The crystal is potentially used for green and infrared eye-safe lasers.     

双程掺镱光纤放大器的增益特征及优化

比较了掺钕光纤和掺镱光纤对1064 nm光放大的特点.基于速率方程和传输方程,数值分析了在915 nm泵浦下双程掺镱光纤放大器的增益特征,并且和传统的单程放大进行了比较.分析了信号光和泵浦光,以及粒子数沿着光纤方向的分布特点.最后对双程掺镱光纤放大器进行了优化.     

近红外光谱分析技术

介绍了近红外光谱分析技术的工作原理,阐述了其数学模型的建立及分析过程,总结了现有常用的化学计量学方法及各自的优点,最后简单的概括了近红外光谱分析技术的应用,尤其是在制药方面的应用.     

Kernel representation-based nearest neighbor classifier

An improvement to the nearest neighbor classifier (INNC) has shown its excellent classification performance on some classification tasks. However, it is not very clearly known why INNC is able to obtain good performance and what the underlying classification mechanism is. Moreover, INNC cannot classify low-dimensional data well and some high-dimensional data in which sample vectors belonging to different class distribution but have the same vector direction. In order to solve these problems, this paper proposes a novel classification method, named kernel representation-based nearest neighbor classifier (KRNNC), which can not only remedy the drawback of INNC on low-dimensional data, but also obtain competitive classification results on high-dimensional data. We reveal the underlying classification mechanism of KRNNC in details, which can also be regarded as a theoretical supplement of INNC. We first implicitly map all samples into a kernel feature space by using a nonlinear mapping associated with a kernel function. Then, we represent a test sample as a linear combination of all training samples and use the representation ability to perform classification. From the way of classifying test samples, KRNNC can be regarded as the nonlinear extension of INNC. Extensive experimental studies on benchmark datasets and face image databases show the effectiveness of KRNNC.     

V形固体激光腔的动力学分析与改进

对通用的V形固体激光腔进行了全面的动力学分析，指出了它的优缺点，它的致命缺点是在动力学因子1ft≈1l1-f附近出现高损耗的运行区，激光器无法运行.为了克服这一缺点，在一种改进的V形腔基础上提出了一种更为紧凑的V形改进腔. 关键词： 固体激光腔 V形固体激光腔 改进的V形腔     

Effect of pyrolytic polyacrylonitrile on electrochemical performance of Si/graphite composite anode for lithium-ion batteries

The silicon/graphite (Si/G) composite was prepared using pyrolytic polyacrylonitrile (PAN) as carbon precursor, which is a nitrogen-doped carbon that provides efficient pathway for electron transfer. The combination of flake graphite and pyrolytic carbon layer accommodates the large volume expansion of Si during discharge-charge process. The Si/G composite was synthesized via cost-effective liquid solidification followed by carbonization process. The effect of PAN content on electrochemical performance of composites was investigated. The composite containing 40 wt% PAN exhibits a relatively better rate capability and cycle performance than others. It exhibits initial reversible specific capacity of 793.6 mAh g^?1 at a current density of 100 mA g^?1. High capacity of 661 mAh g^?1 can be reached after 50 cycles at current density of 500 mA g^?1.     

Single- and multi-shot laser-induced damages of Ta_2O_5/SiO_2 dielectric mirrors at 1064 nm

Ta2O5/SiO2 dielectric mirrors deposited by ion beam sputtering (IBS) are studied. The multi-shot laserinduced damage threshold (LIDT) and its dependence on the number of shots are investigated, after which we find that the multi-shot LIDT is lower than that of single-shot. The accumulation effects of defects play an important role in the multi-shot laser damage. A simple model, which includes the conduction band electron production vsa multiphoton and impact ionizations, is presented to explain the experimental phenomena.     

First principles simulation technique for characterizing single event effects

This paper develops a new simulation technique to characterize single event effects on semiconductor devices. The technique used to calculate the single event effects is developed according to the physical interaction mechanism of a single event effect. An application of the first principles simulation technique is performed to predict the ground-test single event upset effect on field-programmable gate arrays based on 0.25 μm advanced complementary metal-oxide-semiconductor technology. The agreement between the single event upset cross section accessed from a broad-beam heavy ion experiment and simulation shows that the simulation technique could be used to characterize the single event effects induced by heavy ions on a semiconductor device.     

LD side-pumped 41 W high beam quality acousto-optical Q-switched single-rod Nd:YAG laser

We report a LD side-pumped high beam quality (M _x ² = 1.20 and M _y ² = 1.19) acousto-optic (AO) Q-switched single-rod Nd:YAG laser with a TEM₀₀-mode dynamic stable cavity. At the pump power of 600 W, 41 W TEM₀₀-mode 1064 nm laser was achieved with electro-optical conversion efficiency of 7%. The repetition rate and pulse width were 30 kHz and 102 ns, respectively with pulse energy of 1.4 mJ and peak power of 13 kW. Up to 24 W of 532 nm green laser was generated by external frequency doubling, corresponding to 59% optical conversion efficiency.