小型光系NH_3分子气体远红外激光实验

本文详细介绍最有希望的远红外信号源—光泵远红外激光器（ＯＰＦＩＲＬ）实验系统，并改进了以往的检测方法，同时对ＮＨ_３分子２９２×１０（－６）米的超辐射激光谱线进行了实验研究。     

MOVPE生长GaN的准热力学模型及其相图

本基于准热力学平衡模型对以ＴＭＧａ和ＮＨ３为源的ＭＯＶＰＥ生长ＧａＮ的过程进行了分析，并在此基础上计算了ＭＯＶＰＥ生长ＧａＮ的相图，ＧａＮ的ＭＯＶＰＥ相图由ＧａＮ（ｓ）单聚集相区，ＧａＮ（ｓ）＋Ｇａ（ｌ）双凝聚相区，表面会形成Ｇａ滴的两个腐蚀区构成，本着重讨论了生长温度，反应室压力，载气组分，ＮＨ３分解率和Ｖ／Ⅲ比对ＧａＮ单凝聚相区边界的影响。     

光泵远红外激光AC Stark分裂的频谱特性

利用三能级近似和多组三能级近似模型的光泵远红外激光增益解析表达式，通过迭代运算得到了ＣＯ２－１０Ｒ（８）泵浦ＮＨ３分子远红外激光的工作气压与输出光强的关系曲线和ＡＣＳ６ａｒｋ分裂的频谱曲线，以及最佳工作气压的理论值。     

NH_3－氮化N_2O~－生长氧化物的MOS特性

ＮＨ＿３－氮化Ｎ＿２Ｏ￣－生长氧化物的ＭＯＳ特性＝ＭＯＳｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆＮＨ＿３ｎｉｔｒｉｄｅｄＮ＿２Ｏ￣－ｇｒｏｗｎｏｘｉｄｅｓ［刊，英］／Ｙｏｏｎ，Ｇ，Ｗ．…／／ＩＥＥＥＥｌｅｃ－ｔｒｏｎＤｅｖｉｃｅＬｅｔｔｅｒｓ．１９９３，１...     

Al0.85Ga0.15As/GaAs太阳能电池器件工艺优化研究

报道了优化的ｐ－ｎ型Ａｌ０．８５Ｇａ０．１５Ａｓ／ＧａＡｓ太阳能电池器件工艺。分别采用真空蒸发Ｃｒ／Ａｕ和ＡｕＧｅＮｉ／Ａｕ制作下面栅线和背面电极,并分别在４５０℃和３５０℃下快速合金化形成欧姆接触。采用ＮＨ４ＯＨ：Ｈ２Ｏ２：Ｈ３ＰＯ４：Ｈ２Ｏ体系的选择性腐蚀液去除高掺杂的ＧａＡｓ接触层。采用真空蒸发技术制备ＺｎＳ／ＭｇＦ２双层复合减反射层。测试结果表明,采用优化工艺制备的器件的光电转换效率得到了     

三维动画软件SOFTIMAGE3DforWindowsNT版本问世

三维动画软件ＳＯＦＴＩＭＡＧＥ３ＤｆｏｒＷｉｎｄｏｗｓＮＴ版本问世在电脑动画界颇有名气的ＳＯＦＴＩＭＡＧＥ公司和其在中国的唯一代理商－－亚洲电脑顾问有限公司，最近在北京共同发布了其三维动画软件ＳＯＦＴＩＭＡＧＥ３ＤＦｏｒＷｉｎｄｏｗｓＮＴ版本，正式宣...     

Ku波段倍频放大组件

本文报道了一个Ｋｕ波段倍频放大组件的研究结果。输入信号采用ＦＥＴ二倍频，经过ＰＩＮ二极管调制器，最终由Ｋｕ波段栅控脉冲功率放大器输出。在２ｆ０±０．３（ｆ０＝８．２５ＧＨｚ）范围内，脉宽１０μｓ，占空比１０％，脉冲输出的功率大于０．５Ｗ，脉冲前后沿小于２０ｎｓ隔离度大于５０ｄＢ．     

电源电压＋3．3VGaAsFET放大IC

电源电压＋３．３ＶＧａＡｓＦＥＴ放大ＩＣ据《日经工》１９９４年第６０１期报道，日本三菱电机公司已研制成电源电压＋３．３Ｖ，饱和输出３１．８ｄＢｍ（约１．５Ｗ）的ＵＨＦ频段的放大ＩＣ，用于移动通信的移动电台。输入信号频率为９３５ＭＨｚ，附加效率为５７．...     

GaAs（100）表面钝化和Mg／S／GaAs界面的SRPES研究

应用同步辐射光电子谱（ＳＲＰＥＳ）表征了一种新的ＣＨ３ＣＳＮＨ２／ＮＨ４ＯＨ溶液体系处理的ＧａＡｓ（１００）表面的成键特性和电子态．结果表明，经过处理的ＧａＡｓ（１００）表面，Ｓ既与Ａｓ成键也与Ｇａ成键，形成了Ｓ与ＧａＡｓ的新界面，这说明ＣＨ３ＣＳＮＨ２／ＮＨ４ＯＨ溶液处理的ＧａＡｓ（１００）表面具有明显的钝化作用．钝化表面退火处理后，发现ＡＳ的硫化物不稳定，分解或反应生成Ｇａ－Ｓ成分和元素态Ａｓ；室温下，Ｍｇ淀积硫钝化的ＧａＡｓ表面的实验结果表明，Ｍｇ置换ＧａＳ的Ｇａ成为金属Ｇａ偏析到表面，而硫以ＭｇＳ     

2．4Gb／s跨阻型光前置放大器CAD及验证

阐述了光纤通信前置放大器的设计原理，分析了光接收机中ＰＩＮ二极管和ＧａＡｓＦＥＴ器件的信号模型和噪声模型，提取了放大器用ＧａＡｓＦＥＴ器件的模型参数（包括大信号、小信号和噪声模型参数）。利用ＰＳＰＩＣＥ程序对光前置放大器进行了模拟分析和优化设计，并实际制作了用于２．４Ｇｂ／ｓ光纤通信的ＰＩＮ－ＨＥＭＴ前置放大器。实测结果表明放大器３ｄＢ带宽达到ＤＣ～４．４ＧＨｚ，增益为１８±１ｄＢ；加入ＰＩＮ二极管后的光接收模块的３ｄＢ带宽为ＤＣ～１．６８８ＧＨｚ，满足了２．４Ｇｂ／ｓ光纤通信的需要。     

The energy exchange and the optimum length of the sample tube of opfirl

The energy exchange between the pumping laser and FIR signal in the optically pumped FIR laser (OPFIRL) system was studied. The iteration method has been used to calculate the power density of the pumping and FIR signals at any point along the optical axis of the sample tube. It was found that the power density of the FIR signal did not always increase along the length of the laser tube. There was a maximum FIR power density at the appropriate point in the sample tube. If the distance of maximum power point from the entrance of the OPFIRL tube was taken as the length of sample tube Z_opt, the maximum FIR laser output should be obtained. This was the optimum length of OPFIRL tube. The value of Z_opt was closely related to the parameter of OPFIRL such as the pumping power density, the pumping detuning and the frequency of the FIR laser. The energy-exchange and the maximum output of the fir laser were calculated under the ideal condition.     

Laser induced line narrowing and saturation broadening effects in OPFIRL

The variation of the laser linewidth within an optically pumped NH3 FIR laser has been studied theoretically on the basis of three-level quantum system approach. It has been shown that the activated medium within the sample tube of an optically pumped ASE FIR laser can be divided into three regions: A). Laser induced line narrowing region, in which the FIR laser linewidth is less than Lorentz linewidth; B). Saturation broadening region, in which the power density of the FIR. signal becomes large enough to make saturation effect important and the linewidth broadens; C), Self-absorption narrowing region, in which the pumping energy density is below the threshold, so self-absorption dominates and the linewidth decreases. The necessary linewidth of the OPFIRL can be obtained by appropriate selection of the length of the sample tube.     

Spectral Characteristics Comparison of Pulsed Optically Pumped NH3 and CH3OH Far-Infrared Laser

By solving the density matrix equations of a quantum system, the output power intensity of pulsed optically pumped NH3 and CH3OH far-infrared laser (OPFIRL) was calculated respectively by means of iteration method. Based on the calculations, the spectral characteristics of pulsed NH3-OPFIRL and CH3OH-OPFIRL were studied and compared theoretically. The differences of spectral characteristics between the NH3-OPFIRL and CH3OH-OPFIRL were found. Experimentally, a series of FIR emissions of NH3 and CH3OH cavity lasers pumped by TEA-CO2 laser were measured, and the experimental results were in agreement with theoretical calculations.     

Energy Exchanged Process of Superradiant Optically Pumped Far-Infrared Laser with Buffer Gas

By means of solving the density matrix equations, base on the mechanism model of buffer gas, the output intensity of FIR and the FIR signal gain coefficient Gs and IR pumping signal absorption coefficient Gp were calculated, energy exchanged process of superradiant OPFIRL with buffer gas was analyzed. It was found that after adding buffer gas into the laser medium, the FIR output could be increased, and the active region of a FIR laser was lengthened.     

光泵亚毫米波激光的工作参数优化的研究

文章对光泵亚毫米波激光器工作参数的优化进行了理论研究。在不假定B_2≈0的情况下,求解量子系统的密度矩阵方程,并计算了光泵亚毫米波激光的输出功率密度,计算结果与文献报导的实验结果较好地相符。在此基础上,计算求得了光泵亚毫米波激光器的最佳泵浦功率、样品管的长度和激光器工作气体的最佳压强。还发现了这些参数之间是相互制约的。应用这些结果,人们有可能采用理论计算方法,设计工作在最佳状态下的亚毫米波激光器。     

Study of the spectral characteristics and the output coupling of pulse optically pumped cavity SMMW laser

The miniaturization of OPFIRL plays an important role in application of this new wavelength range of electromagnetic wave, especially in that of spaceflight where efficiency and miniature are emphasized.[1][8] So it is important to optimize the operating parameters of OPFIRL. This article will start with density matrix equations, then calculate the FIR output power density under different operating conditions by means of iteration calculation. And then parameters of the laser will be changed in order to study it's spectral characteristic of the FIR laser. We found that, working under the optimum operating gas pressure, FIF output power varies with the output coupling of the cavity OPFIRL. There is an optimum value of reflection coefficient R_o of the output window which makes the output FIR power denity and spectral characteristic of miniature OPFIRL optimum.     

单、双纵模腔式光泵远红外激光器的实验研究

实验上采用可选纵模的TEA－CO2激光器作泵浦源,用CO2－9R（16）线泵浦小型腔式NHG3远红外激光器,在单、双纵模泵浦条件下均获得波长为90．4μm的远红外谱线。对单、双纵模腔式光泵远红外激光的输出特性和工作气压作了实验比较研究,发现双纵模腔式光泵远红外激光可获得更强的远红外输出,具有较低的最佳工作气压值,并可在较宽的气压范围内工作。     

A very short OPFIR superradiant laser

A very short OPFIR superradiant laser was studied theoretically and experimentally. The density matrix equations of a three-level quantum system for NH₃ gas was solved for the gains of the FIR signal and the IR signal in the very short OPFIRL system. The output characteristics of the OPFIR superradiant laser were calculated numercally. A curve showing the relation between the length of the sampe tube of the OFFIRL and the corresponding optimum pressure was obtained. In our experiment, a 10cm OPFIRL and a 5cm OPFIRL were constructed and operated successfully. The output characteristics were meassured and the calculated results were verified.     

缓冲气体对超辐射光抽运远红外激光器的影响

以NH3作为远红外激光的工作气体 ,以N2 作为缓冲气体 ,对加入缓冲气体前后的小型超辐射光抽运远红外激光器作理论比较研究。基于缓冲气体作用机理模型 ,计算出激光工作物质的综合弛豫时间 ;通过解半经典的密度矩阵方程 ,计算出远红外激光输出的频谱特性和工作气压。计算表明 ,加入缓冲气体后 ,远红外激光的输出得到提高 ;存在一个最佳混合气体比例 ,在这一比例下远红外激光输出达到最大 ;加入缓冲气体后 ,最佳工作气压比加入缓冲气体前获得提高。     

Design consideration of miniature OPFIRL. II. Popt of miniature cavity OPFIRL affected by Ro

The influence of the optimum parameters of mini-OPFIRL by the output couple of laser cavity was studied theoretically. The Density Matrix treatment is applied to a three-level system for steady state. The Density Matrix equations were solved under the assumption that Is ? 1E–13 w/cm² equal to the actual FIR power density at any points in the sample tube. Through numerical calculations, we found that the output coupling of OPFIRL affected seriously the energy exchange between pumping signal and FIR signal the stored energy of FIR signal and the optimum operating gas pressure. These problems are important to design a practical miniature OPFIRL.