基于探针光调制的皮秒分辨X-ray探测方法与实验

高能密度物理研究中涉及许多单次皮秒现象的诊断测量, 然而对单次X-ray脉冲形状、X-ray与激光脉冲的皮秒精度同步依然是极具挑战的课题. 传统行波选通分幅相机受电子渡越时间限制, 难以突破40 ps时间分辨极限. 本文围绕半导体中光学探针光的全光调制效应, 提出一种以低温GaAs材料为基础, 实现皮秒时间分辨X-ray探测的新方法, 详细阐述了该探测器的工作机理、器件参数设计和时间分辨能力. 通过飞秒激光打靶实验, 验证了其概念设计的正确性. 结果表明该探测器具有约1.5 ps时间响应和10 ps时间分辨能力, 通过材料优化可将时间分辨提升 至1 ps以内.     

GENERATION OF MULTI-WAVELENGTH VISIBLE LIGHT IN Er3+-DOPED AND Er3+/Yb3+-DOPED SINGLE-MODE OPTICAL FIBER PUMPED AT 1313 nm

We report the generation of multi-wavelength visible light through amplified spontaneous emission (ASE) in Er³⁺-doped and Er³⁺/Yb³⁺-doped germanosilicate single-mode optical fiber pumped by a Nd:YLF laser at 1313nm. In the Er³⁺-doped fiber, the intense multi-wavelength blue emission hnes around 463-510nm corre-spond to transitions born ²G_7/2 etc. excited states to the metastable ⁴I_13/2 state, and their pumping mechanists is aecomphshed by a stepwise four-photon absorption. Some emission hnes in this wavelength region are attributed to the three-wave sum-frequency process of 1313 and 1530nm (corresponds to ⁴I_13/2 -⁴I_15/2). The intense green emission hnes at 525 and 540 nm are also observed in the Er³⁺-doped fiber. In the Er³⁺/Yb³⁺-doped fiber the blue and green lines are very weak compared with those in the Er³⁺-doped fiber.     

红外InGaAsP光电阴极研究

本文主要对阈值波长可达1.25μm的InGaAsP光电阴极进行了详细的研究。在国内首次实现了在0.5μm～1.25μm波段范围内具有光电响应的半导体光电阴极。用Cs和O₂激活后得到的光电阴极在1.06μm处的反射式光电灵敏度为3.4mA/W,量子效率为0.4%。本文还对激活表面及热清洁工艺进行了系统地分析,确定出了最佳的表面清洁温度及时间。     

GENERATION OF MULTI-WAVELENGTH VISIBLE LIGHT IN Er3+-DOPED AND Er3+/Yb3+-DOPED SINGLE-MODE OPTICAL FIBER PUMPED AT 1313 nm

We report the generation of multi-wavelength visible light through amplified spontaneous emission (ASE) in Er³⁺-doped and Er³⁺/Yb³⁺-doped germanosilicate single-mode optical fiber pumped by a Nd:YLF laser at 1313nm. In the Er³⁺-doped fiber, the intense multi-wavelength blue emission hnes around 463-510nm corre-spond to transitions born ²G_7/2 etc. excited states to the metastable ⁴I_13/2 state, and their pumping mechanists is aecomphshed by a stepwise four-photon absorption. Some emission hnes in this wavelength region are attributed to the three-wave sum-frequency process of 1313 and 1530nm (corresponds to ⁴I_13/2 -⁴I_15/2). The intense green emission hnes at 525 and 540 nm are also observed in the Er³⁺-doped fiber. In the Er³⁺/Yb³⁺-doped fiber the blue and green lines are very weak compared with those in the Er³⁺-doped fiber.     

1.25μm InGaAsP光电阴极的研究

使用Ⅲ-Ⅴ族化合物半导体光电阴极的光电成像器件在光纤通讯、医学、夜视以及其它科研领域有着广泛的用途。其核心部件是二元、三元或四元化合物半导体材料光电阴极。国外在对阈波长为0.9μm的GaAs负电     

X射线皮秒分幅相机技术的初步研究

本文介绍了我们正在研究的x射线皮秒分幅相机技术的最新理论和实验研究结果。我们提出了一种新的实现皮秒分幅的技术方案。设计了适合于本方案的新型变象管。用直流X射线源测得该管的静态空间分辨举为201p/mm,并得到了四幅准静态分幅象。用激光打靶产生的脉冲x射线初步测量了脉冲静态和动态空间分辨率,拍摄到了单幅动态照片。     

X射线皮秒条纹相机时间分辨率测试

本文从X射线皮秒条纹变象管的工作原理入手,分析了影响X射线条纹相机时间分辨率的因素,就我所研制的X射线条纹相机的时间分辩率进行了测量。条纹相机中应用全雪崩晶体管高速扫描线路。它具有抖动小、延时小寿命长的特点。X射线皮秒脉冲是用激光打靶的方法产生。为了得到窄的X射线脉冲,用非共振环型腔YAG激光器作为激     

匹配In_(0.53)Ga_(0.47)As/InP量子阱材料的GSMBE生长及特性分析

在国产CBE设备上，用GSMBE方法首次在国内成功地生长出了具有不同阱宽（1～18nm）的高质量的In0.53Ga0.47As／InP匹配量子阱结构材料，低温光致发光谱测试结果表明：量子阱材料发光谱峰强且锐，每个阱的激子跃迁峰清晰可辨．当阱宽大于6nm时，阱中激子跃迁能量的实验值与理论计算值符合得很好；当阱宽小于6nm时，实验值小于理论值；对阱宽相同的窄阱而言，我们样品的实验值高于Tsang的实验值，当阱宽小于4nm时，阱中激子跃迁谱峰的半高宽小于当量子阱界面起伏一个分子单层时所引起的展宽值，表明量子阱的界面具有原子级的平整度；与1nm阱相应的低温光致     

啁啾脉冲激光放大的数值分析

 从Maxwell波动方程出发,建立了描述脉冲在啁啾放大系统中传播的非线性薛定谔方程;采用数值计算,系统地分析研究了放大过程中的各种效应对脉冲的影响,给出了啁啾脉冲在频域、时域内及放大压缩后脉冲信噪比的动态演化特征;讨论了展宽器附加色散量在放大过程中的影响。     

高组份Al值的AlxGa1-x As和AlxGa1-x As/GaAs/AlxGa1-xAs/GaAs多层结构的MOCVD生长

用自制常压MOCVD系统,在半绝缘GaAs衬底上生长高Al组份Al_xGa_1-xAs（其x值达0.83）,和Al_xGa_1-xAs/GaAs/Al_xGa_1-xAs/GaAs多层结构,表面镜面光亮。生长层厚度从几十到十几μm可控,测试表明外延层晶格结构完整,x值调节范围宽,非有意掺杂低,高纯GaAs外延层载流子浓度n_300K=1.7×10¹⁵cm^-3,n_77K=1.4×10¹⁵cm^-3,迁移率μ_300K=5900cmcm²/V.S,μ_77K=55500cm²/V.S。用电子探针,俄歇能谱仪测不出非有意掺杂的杂质,各层间界面清晰平直。 对GaAs,AlGaAs生长层表面缺陷,衬底偏角生长温度及其它生长条件也进行了初步探讨。