共查询到20条相似文献,搜索用时 93 毫秒
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外腔式激光器的简易调试方法杨立森(内蒙古师范大学物理系呼和浩特010022)外腔式激光器的寿命在一年半到两年左右,如自己更换新管,可以节省不少的费用.外腔式激光器的构造如图1,A为前反射镜,是镀膜半透半反镜,其法线方向可由前面的两个旋钮调节.B为后反... 相似文献
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InGaAsP—InP大光腔结构激光器 总被引:3,自引:1,他引:2
本文针对影响InGaAsP-InP激光器温度特性的各种因素,设计并制备了大光腔(LOC)结构激光器.实验表明,这种结构改善了激光器的温度稳定性,获得了低阈值(宽接触型器件J_(th)≈2.5kA/cm~2),高功率(脉冲输出3W)和高特征温度(T_o=150K)器件. 相似文献
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用量子阱激光器增益与载流子浓度的对数关系(增益饱和效应)取代了体材料的线性关系,得到了适用于量子阱结构的速率方程。详细分析和计算了这一修正的影响。计算表明,对长腔(低损耗)器件线性关系是较好的近似;对短腔(高损耗)、线性关系则有较大的误差,必须考虑增益饱和的影响,否则将过高估算自发辐射因子的测量值,过高估计弛豫振荡频率和最大调制频率。这一结果对微腔激光器的研究具有重要的意义。 相似文献
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报道用971nm半导体激光器泵浦的掺铒光纤激光器的一些实验研究结果。演示了由光纤环反射器和光纤光栅构成的全光纤色散掺铒光纤激光器,在1.55μm波段获得了线宽小于0.05nm的激光输出。 相似文献
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报道了用一个3W激光二极管端面泵浦Nd:YMA激光器。实验采用三镜折叠象散补偿腔。在1054mm波长,激光器CW输出功率达230mW,斜率效率为38%,光-光转换效率9.5%, 相似文献
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线形腔掺铒光纤激光器输出特性的理论研究 总被引:5,自引:0,他引:5
通过求解速率方程,从理论上详细地分析了形腔掺铒光纤激光器输出特性,得到了稳定条件下激光器阈值泵浦功率,输出功率和斜率效率的解析表达式;给出了构造线形腔掺铒光行激光器所需掺铒光纤最短长度和最佳长度的表达式。 相似文献
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选频元件谱线宽度对可调谐外腔半导体激光器的影响 总被引:1,自引:0,他引:1
在可调频外腔半导体激光器(ECLD)中,选频元件的响应函数具有一定的频谱宽度,本文研究了该宽度对外腔半导体体激光器的影响,导出了为实现外腔半导体激光器的连续调谐所需的该宽度上限的表达式,求得了该响应的峰值频率与振荡频率之间的差别。 相似文献
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This paper proposes two measures for the evaluation of permutation techniques used in image encryption. First, a general mathematical framework for describing the permutation phase used in image encryption is presented. Using this framework, six different permutation techniques, based on chaotic and non-chaotic generators, are described. The two new measures are, then, introduced to evaluate the effectiveness of permutation techniques. These measures are (1) Percentage of Adjacent Pixels Count (PAPC) and (2) Distance Between Adjacent Pixels (DBAP). The proposed measures are used to evaluate and compare the six permutation techniques in different scenarios. The permutation techniques are applied on several standard images and the resulting scrambled images are analyzed. Moreover, the new measures are used to compare the permutation algorithms on different matrix sizes irrespective of the actual parameters used in each algorithm. The analysis results show that the proposed measures are good indicators of the effectiveness of the permutation technique. 相似文献
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K. Henschel B. Hellwig F. Amtage J. Vesper M. Jachan C. H. Lücking J. Timmer B. Schelter 《The European physical journal. Special topics》2008,165(1):25-34
The analysis of multi-dimensional biomedical systems requires analysis techniques, which are able to deal with multivariate
data consisting of both time series as well as point processes. Univariate and bivariate analysis techniques in the frequency
domain for time series and point processes are established and investigated, although the number of investigations is strongly
biased towards time series. Actual multivariate techniques for time series or hybrids of time series and point processes are
scarcely addressed. Here, we present spectral analysis techniques which are able to analyse point processes as well as time
series. Thereby, univariate, bivariate as well as multivariate techniques are discussed. Applications to simulated as well
as real-world data reveal the abilities of the proposed techniques. 相似文献
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The problem of impurity accumulation in a tokamak and some possible control techniques to counteract such problems are reviewed. The techniques discussed are primarily those that have been studied at General Atomic Company (GA). The possible application of such impurity control techniques in the future Engineering Test Facility (ETF) is also discussed. 相似文献
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AR Engel 《Contemporary Physics》2013,54(6):523-526
This article reviews some of the applications of physics to the solution of archaeological problems. The use of magnetic, resistivity and electromagnetic surveying techniques for the location of buried features is described. Various methods of age determination are outlined while the problems associated with radiocarbon dating of organic material and thermoluminescent dating of pottery are discussed in detail. The techniques, including petrological examination, chemical analysis and isotopic analysis, employed in the physical examination of archaeological artefacts are described. Examples of the application of these techniques in establishing the source of the raw materials used in pottery, metal and stone implements and in elucidating the techniques of manufacture of pottery and metal objects are also given. 相似文献
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The biosciences require the development of methods that allow a non-invasive and rapid investigation of biological systems. In this aspect, high-end imaging techniques allow intravital microscopy in real-time, providing information on a molecular basis. Far-field fluorescence imaging techniques are some of the most adequate methods for such investigations. However, there are great differences between the common fluorescence imaging techniques, i.e., wide-field, confocal one-photon and two-photon microscopy, as far as their applicability in diverse bioscientific research areas is concerned. In the first part of this work, we briefly compare these techniques. Standard methods used in the biosciences, i.e., steady-state techniques based on the analysis of the total fluorescence signal originating from the sample, can successfully be employed in the study of cell, tissue and organ morphology as well as in monitoring the macroscopic tissue function. However, they are mostly inadequate for the quantitative investigation of the cellular function at the molecular level. The intrinsic disadvantages of steady-state techniques are countered by using time-resolved techniques. Among these fluorescence lifetime imaging (FLIM) is currently the most common. Different FLIM principles as well as applications of particular relevance for the biosciences, especially for fast intravital studies are discussed in this work. 相似文献
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The biosciences require the development of methods that allow a non-invasive and rapid investigation of biological systems.
In this aspect, high-end imaging techniques allow intravital microscopy in real-time, providing information on a molecular
basis. Far-field fluorescence imaging techniques are some of the most adequate methods for such investigations. However, there
are great differences between the common fluorescence imaging techniques, i.e., wide-field, confocal one-photon and two-photon
microscopy, as far as their applicability in diverse bioscientific research areas is concerned. In the first part of this
work, we briefly compare these techniques. Standard methods used in the biosciences, i.e., steady-state techniques based on
the analysis of the total fluorescence signal originating from the sample, can successfully be employed in the study of cell,
tissue and organ morphology as well as in monitoring the macroscopic tissue function. However, they are mostly inadequate
for the quantitative investigation of the cellular function at the molecular level. The intrinsic disadvantages of steady-state
techniques are countered by using time-resolved techniques. Among these fluorescence lifetime imaging (FLIM) is currently
the most common. Different FLIM principles as well as applications of particular relevance for the biosciences, especially
for fast intravital studies are discussed in this work.
相似文献
20.
Acoustic source localization 总被引:1,自引:0,他引:1
In this article different techniques for localizing acoustic sources are described and the advantages/disadvantages of these techniques are discussed. Some source localization techniques are restricted to isotropic structures while other methods can be applied to anisotropic structures as well. Some techniques require precise knowledge of the direction dependent velocity profiles in the anisotropic body while other techniques do not require that knowledge. Some methods require accurate values of the time of arrival of the acoustic waves at the receivers while other techniques can function without that information. Published papers introducing various techniques emphasize the advantages of the introduced techniques while ignoring and often not mentioning the limitations and weaknesses of the new techniques. What is lacking in the literature is a comprehensive review and comparison of the available techniques; this article attempts to do that. After reviewing various techniques the paper concludes which source localization technique should be most effective for what type of structure and what the current research needs are. 相似文献