不同方法制备的C60材料的发光行为

采用Ｓｏｌ－Ｇｅｌ溶胶－凝胶的方法出了掺杂Ｃ６０的Ｎａ２Ｏ－Ｂ２Ｏ３－ＳｉＯ２干凝胶和掺杂Ｃ６０的ＳｉＯ２ＰＤＭＳ（聚二甲基硅氧烷）的凝胶材料。测量了纯Ｃ６０粉的吸收光谱和掺杂Ｃ６０偻的凝胶材料在不同温度下的发射光谱。观测到了Ｃ６０／ＮＢＳ在３０Ｋ～２００Ｋ温度范围Ｃ６０的发光峰位于１．６９ｅＶ,发光峰随着温度的升高向低能边有一较小偏移,并且谱峰强度减弱。对实验数据进行了拟合。分析了发光与温度的关     

掺铒光纤放大器噪声特性的全面分析

本文对掺铒光纤放大器（ＥＤＦＡ）的噪声特性进行了全面的分析。把光信号和ＥＤＦＡ中放大自发辐射（ＡＳＥ）产生的量子噪声，以及信号－ＡＳＥ拍频噪声和ＡＳＥ－ＡＳＥ拍频噪声一并加以考虑。通过数值模拟，给出了不同信号功率和泵浦功率下的ＥＤＦＡ噪声系数。这些结果对优化ＥＤＦＡ的工作参量及其工程制作具有一定的指导作用。     

超薄SiO2层的热生长

隧道小孔中超薄ＳｉＯ２的生长是ＥＥＰＲＯＭ电路制造的关键工艺之一。采用ＳＵＰＲＥＭ－Ⅲ工艺模拟程序对超薄ＳｉＯ２的热生长进行了工艺模拟，经过大量的工艺实验及优化，确定了超薄ＳｉＯ２的最佳生长条件，生长出的ＳｉＯ２性能良好，完全可满足ＥＥＰＲＯＭ研制的要求。     

用于MFIS的铁电薄膜刻蚀技术研究

制备ＭＦＩＳ存储器的铁电薄膜一般选用抗疲劳特性好的ＳＢＴ铁电薄膜,介质层一般选用ＺｒＯ２作为阻挡层,以克服电荷注入效应,改进器件的性能。在ＭＦＩＳ研制中,ＳＢＴ薄膜和ＺｒＯ２薄膜的刻蚀是关键工艺之一。研究了用ＳＦ６和Ａｒ作为反应气体刻蚀ＳＨＢＴ及ＺｒＯ２薄膜的方法,对不同条件下ＳＢＴ和ＺｒＯ２的刻蚀速率进行了实验研究和讨论、分析,得到了刻蚀ＳＢＴ及ＺｒＯ２的优化工艺条件。     

量子阱无序的窗口结构InGaAs/GaAs/AlGaAs量子阱激光器

对ＳｉＯ２薄膜在快速热退火条件下引起的空位诱导ＩｎＧａＡｓ／ＧａＡｓ应变量子阱无序和ＳｒＦ２薄膜抑制其量子阱无序的方法进行了实验研究。并将这两种技术的结合（称为选择区域量子阱无序技术）应用于脊形波导ＩｎＧａＡｓ／ＧａＡｓ／ＡｌＧａＡｓ应变量子阱激光器，研制出具有无吸收镜面的窗口结构脊形波导量子阱激光器。该结构３μｍ条宽激光器的最大输出功率为３４０ｍＷ，和没有窗口的同样结构的量子阱激光器相比，最大输出功率提高了３６％。在１００ｍＷ输出功率下，发射光谱中心波长为９７８ｎｍ，光谱半宽为１．２ｎｍ。平行和垂直方向远场发散角分别为７．２°和３０°     

SnO_2陶瓷材料的制备及其气敏特性

研究了Ｓｎ粒的硝酸氧化法、ＳｎＣｌ２溶液化学沉淀法、ＳｎＣｌ２与ＳｎＣｌ４混合盐沉淀法及Ｎａ２ＳｎＯ３溶液化学沉淀法等合成纳米ＳｎＯ２气敏材料的工艺条件、产率、结构和气敏性能及Ａｕ、Ａｇ、Ｐｄ、Ｐｔ等贵金属对不同工艺ＳｎＯ２的气体灵敏度和气敏选择性的影响。实验结果表明,制备工艺,颗粒尺寸,掺杂元素和工作温度等对ＳｎＯ２的气敏特性有影响。     

采用锗硅异质外延方法制备硅量子线

报道了一种采用锗硅异质外延制备硅量子线的新方法。在超低压化学气相淀积外延生长Ｓｉ／ＳｉＧｅ／Ｓｉ异质结构基础上，采用光刻和反应离子刻蚀技术形成槽状图形，用选择腐蚀液进行选择化学腐蚀，获得Ｓｉ线阵列，最后通过湿氧、干氧氧化过程，成功实现了高质量Ｓｉ／ＳｉＯ２异质界面结构硅量子线。采用扫描电子显微镜对量子线形成特征进行了研究，并讨论了硅线的热氧化性质。     

制备条件对SnO_2／Si性质的影响

研究了沉积温度、ＳｎＣｌ４溶液的浓度、掺Ｐｄ等对ＳｎＯ２／Ｓｉ光电压的影响，测量了ＳｎＯ２／Ｓｉ的光电压谱，得出最佳的制备条件，进行了有关计算和分析。     

激光诱导H_2S催化裂解制备H_2的研究

在室温常压静态条件下研究了以Ｖ２Ｏ５／ＴｉＯ２为催化剂，紫外脉冲激光诱导Ｈ２Ｓ催化分解为Ｈ２和Ｓ的反应及其机理。考察了产氢量与激光不同照射条件之间的关系。     

GaAs抛光片腐蚀过程初步研究

采用Ｘ射线衍射、Ｘ射线双晶衍射和Ｘ射线荧光三种手段对经Ｈ２ＳＯ４：Ｈ２Ｏ２：Ｈ２Ｏ＝１６：１：１和３：１：１腐蚀液,在不腐蚀条件下得到的ＧａＡｓ片子进行近表层结晶完整性、片子表面的残留产物以及发射二次Ｘ射线情况测量,并初步分析了这些数据。     

双窗口电磁诱导透明的相干瞬态研究

通过求解准A-型四能级系统的含时密度矩阵方程,研究了系统从单窗口电磁诱导透明(EIT)向双窗口EIT转换的相干瞬态过程.该过程表现为一种量子拍频形式,并利用缀饰态理论很好地解释了量子拍频的规律,指出这种量子拍频效应源于射频驱动场所引起劈裂能级间的量子相干.结果表明:当探测场与相应的裸态跃迁能级共振作用时,拍频频率等于射频驱动场Rabi频率的二分之一;当探测场与强射频驱动场和原子系统相互作用所产生的缀饰态跃迁能级共振时,拍频频率等于射频驱动场的Rabi频率.     

The self-injected nonmode-locked picosecond laser

A new type of laser which generates picosecond pulses is presented. 6 ps, ∼ 1 GW, 3 pps,lambda = 1.06 mum in a single pulse are obtained with good stability. Accurate timing of the pulses can be achieved, and no external pulse selection is required. In our laser, the pulse does not develop from quantum noise, but is the result of a nonlinear frequency and time processing in the cavity of a seed pulse that is coherent from the beginning of the shortening process. We believe that the remarkable characteristics of pulse stability are at least partially due to these considerations in coherence.     

脉冲式赝热光源的实验研究

高亮度的辐照热光源一定程度上限制了基于经典热光场的强度关联量子成像技术的实验研究和广泛应用.因为一般热光源相干时间极短,且每个相干元胞内光子数少(亮度低),而采用激光照射旋转毛玻璃形成的动态散斑作为赝热光场可以解决上述问题.当采用的是纳秒脉冲激光时,得到的赝热光场除了能极大程度地模拟真实热光场的热涨落,光场涨落服从真实热光场所具有的高斯统计分布以外,另一个最重要的特性是光场涨落的测量不受光电探测系统有限通频带的限制,即使是慢响应探测电路,也能准确地记录光场抖动,即该光场符合交叉谱纯条件.     

Analysis of beat noise in coherent and incoherent time-spreading OCDMA

The effect of beat noise and other types of additive noise in time-spreading optical-code-division multiple-access (TS-OCDMA) networks is analyzed in this paper. By defining the coherent ratio kt, the ratio of the chip duration to the coherence time of the light source, TS-OCDMA systems are classified into incoherent, partially coherent, and coherent systems. The noise distributions and the bit-error rates are derived, and system performance is discussed for different cases. The performance of coherent systems is limited by the beat noise. With increasing kt, the effect of beat noise decreases in incoherent systems, and they eventually become free of beat noise. Possible solutions to the beat noise problem in coherent and partially coherent systems are also proposed and discussed.     

多光子跃迁过程中的量子衍射与量子相干控制

从理论上解释了利用相位调制光场如何实现多光子跃迁的量子相干控制。在弱场作用下研究了几种整形激光脉冲形式与二能级原子系统的相互作用过程,研究了整形激光脉冲作用下双光子过程中的量子衍射效应。利用微扰理论给出了多光子跃迁过程的解析表示,根据解析表示解释了阶跃相位和余弦相位调制光场作用下多光子跃迁几率的量子相干控制。结果表明,这两种相干控制过程中都有跃迁几率消除现象,而且不同调制相位光场的作用结果对应着不同的几率消除位置。     

Analysis of heart rate variability in the presence of ectopic beats using the heart timing signal

The time-domain signals representing the heart rate variability (HRV) in the presence of an ectopic beat exhibit a sharp transient at the position of the ectopic beat, which corrupts the signal, particularly the power spectral density (PSD) of the HRV. Consequently, there is a need for correction of this type of beat prior to any HRV analysis. This paper deals with the PSD estimation of the HRV by means of the heart timing (HT) signal when ectopic beats are present. These beat occurrence times are modeled from a generalized, continuous time integral pulse frequency modulation model and, from this point of view, a specific method for minimizing the effect of the presence of ectopic beats is presented to work together with the HT signal. By using both, a white noise driven autoregressive model of the HRV signal with artificially introduced ectopic beats and actual heart rate series including ectopic beats, the more usual methods of HRV spectral estimation are compared. Results of the PSD estimation error function of the number of ectopic beats are presented. These results demonstrate that the proposed method has one order of magnitude lower error than usual ectopic beats removal strategies in preserving PSD, thus, this strategy better recovers the original clinical indexes of interest.     

Nanostructure optical emitters based on quasibound electron energy levels

Given two energy states (levels) in a quantum well formed by two potential barriers of finite thickness, elementary quantum mechanics tells us that the lower energy state is more tightly bound than the upper state. This produces a longer spatial confinement lifetime in the lower state than in the upper state. This ratio of lifetimes is opposite to that needed for laser action between these states. Furthermore, the lifetime of the lower energy state must be significantly shorter than the electron scattering time for the upper state. These facts have blocked the development of lasers based on these transitions. However, in this paper we report experimental and analytical results on a versatile type of semiconductor heterostructure that overcomes these difficulties. Unlike previous devices, this structure relies on an optical transition between two states which are both above-barrier quasibound states in the ‘classical’ continuum. The oscillator strength is large and the operation of the device clearly demonstrates coherent electron wave behavior. Such structures could represent the basis for a new room-temperature infrared semiconductor laser.     

基于类金刚石沉积的短脉宽XeCl激光设计及脉宽分析

在气体配比HCl:Xe:He=0.12％:1％:98.88％实现了大功率短脉冲XeCl准分子激光器,以纳米异质结构、微观量子阱、表面微小尺度薄膜沉积,镀制金刚石薄膜、半导体薄膜、巨磁薄膜,及外延生长及后续的光刻、激光与物质的相互作用、等离子体研究为目的,设计了高能量、短脉宽脉冲放电激励的XeCl准分子激光器新型结构,完成了脉冲波形测试。试验结果表明:激光脉宽最短13ns,单脉冲能量450mJ,矩形光斑大小2cm×1cm,束散角3mrad,最高重复频率5 Hz。验证了激光器结构、动力学速率方程、总结出了饱和增益、脉宽规律。产生的短脉宽激光热融蚀效应小,类金钢石材料对基底形成了良好的等离子溅射羽辉。     

时变源作用下介观LC电路系统量子态的演化

采用代数动力学规范变换方法,求出含时变电压源的介观LC电路量子态随时间演化算符的精确解,研究含时变电压源的介观LC电路量子态的相干特性.结果表明,电路中电容器储电量q的几率是一个运动的Gauss波包,导出波包中心电量与外电源的一般关系.研究了输入电压源为单矩形脉冲电压的特例.     

强脉冲激光金属表面烧蚀热场的数值仿真

用有限差分法对强脉冲激光难熔金属表面烧蚀过程的温度场进行了三维数值仿真计算。计算模型在能量平衡方程的基础上,将入射的脉冲激光在时间与空间上的分布以Ｇａｕｓｓ分布考虑,同时考虑工件尺寸、工件材料热物理性质及对流辐射造成的表面热损失等对温度场的影响。文章应用交替方向隐式方法建立差分方程,对该数学模型进行计算,数值模拟了难熔金属钛、钼在强脉冲激光烧蚀下的温度场变化,并将数值解与热导方程的解析解进行了分析