理论研究B2分子X3Σg-和A3Πu态的光谱性质

采用Davidson修正的内收缩多参考组态相互作用方法及Dunning等的相关一致基aug-cc-pV6Z计算了B₂分子X³∑_g^-和A³Π_u电子态的势能曲线.利用总能量外推公式,将两个电子态的总能量分别外推至完全基组极限.对势能曲线进行核价相关修正及相对论修正计算,得到了同时考虑两种效应修正的外推势能曲线.通过同位素质量识别,得到了主要的同位素分子¹¹B¹¹B和¹⁰B¹¹B的X³Σ_g^-和A³Ⅱ_u电子态的光谱常数T_e,R_e,ω_e,ω_ex_e,ω_ey_e,B_e,β_e和γ_e.求解双原子分子核运动的径向Schr（o|¨）dinger方程,找到了无转动的同位素分子¹¹B₂（X³Σ_g^-,A³Π_u）和¹⁰B¹¹B（X³∑_g^-,A³Π_u）的全部振动态.针对每一同位素分子的每一振动态,分别计算了其振动能级和惯性转动常数等分子常数,它们均与已有的实验结果较为一致.其中,¹⁰B¹¹B（A^Π_u）分子的光谱常数和分子常数属首次报道.     

非即变相位共轭反馈对半导体激光器动态特性的影响

从四波混频产生相位共轭的物理原因出发,定义了相位共轭镜（PCM）的响应时间．建立起非即变相位共轭反馈条件下半导体激光器的外腔模型。以响应时间及频率失调为参变量,对其分岔及噪声等动态行为进行数值分析。结果表明,不考虑噪声影响时,增加相位共轭镜响应时间会使混沌带出现的次数和范围得到较大的抑制,当响应时间增大到1．5ns时,混沌带消失,半导体激光器保持稳定的单周期状态;考虑噪声影响后,随若响应时间的相对强度噪声（RIN）可减小几dB甚至十几dB,产生突变需要的反馈量也增大一个数量级以上,且其频谱的峰值向高频方向移动;另外,由于共轭反馈引起的频率失调低于半导体激光器激射频率3个数量级以上．它只对分岔特性有影响．对相对强度噪声的影响几乎为零。     

便携式无线人体脂肪率测量仪的设计

生物电阻抗法(BIA)是一种安全非侵入式的、结果可靠有效的人体组成成分(脂肪含量)测量方法。以此为原理,设计了一款便携式无线人体脂肪率测量仪。硬件上,系统以高集成化、低功耗的阻抗测量芯片AD5933为核心,通过蓝牙实现与上位机的无线通信,大大降低了设备的复杂度。软件部分提出一种单频点小阻抗范围的增益系数校准方式,计算量小且容易实现。将新测量仪和欧姆龙体脂仪HBF-358进行对比实验,并作Bland-Altman一致性分析。结果表明,二者的相关系数为0.997。此外,该测量仪还具有易操作、小型化的特点。     

偶氮侧基聚合物光致异构动力学研究

本文对偶氮侧基聚合物相位共轭光时间特性进行了研究,得到了相位共扼光产生机制─光致异构过程的时间常数.在相位共轭光上升阶段,其时间常数在0.4～0.5s之间,在相让共轭光的衰减过程,衰减满足双指数关系,分段拟合得到较好的结果,且得到快过程的时间常数为0.27s,慢过程的时间常数为0.78s.     

Dual-wavelength distributed Bragg reflector semiconductor laser based on a composite resonant cavity

We report a monolithic integrated dual-wavelength laser diode based on a distributed Bragg reflector (DBR) composite resonant cavity. The device consists of three sections, a DBR grating section, a passive phase section, and an active gain section. The gain section facet is cleaved to work as a laser cavity mirror. The other laser mirror is the DBR grating, which also functions as a wavelength filter and can control the number of wavelengths involved in the laser action. The reflection bandwidth of the DBR grating is fabricated to have an appropriate value to make the device work at the dual-wavelength lasing state. We adopt the quantum well intermixing (QWI) technique to provide low-absorption loss grating and passive phase section in the fabrication process. By tuning the injection currents on the DBR and the gain sections, the device can generate 0.596 nm-spaced dual-wavelength lasing at room temperature.     

基于低相干光的阵列透镜束匀滑技术研究

基于激光加载的材料状态方程的实验研究对靶面光强分布的均匀性及稳定性提出了极高的要求,靶面光强的上述两大特性在很大程度上决定了实验结果的精度和可重复性.本文针对传统窄带高相干激光装置在激光加载材料状态方程实验中表现出的靶面光强均匀性和光强分布稳定性两方面可能存在的问题,提出了基于宽带低相干激光,利用消衍射阵列透镜联合诱导非相干技术的束匀滑方案,并重点分析了波前相位畸变对靶面不均匀性及稳定性的影响.模拟结果表明,该方法明显降低了靶面不均匀性,提高了对波前相位畸变的包容度,获得了均匀、稳定的光强分布.统计分析显示,焦斑强度分布极差和不均匀性与波前相位畸变均方根梯度相关性较强.因此,可以根据统计结果以及实验对焦斑强度分布的要求,给出波前相位畸变的容差范围,对状态方程实验中激光驱动器参数的设计与优化具有指导意义.     

Raman and optical absorption spectroscopic investigation of Yb-Er codoped phosphate glasses containing SiO_2

Yb-Er codoped Na2O-Al2O3-P2O5-xSiO2 glasses containing 0 - 20 mol% SiO2 were prepared successfully. The addition of SiO2 to the phosphate glass not only lengthens the bond between pS＋ and non-bridging oxygen but also reduces the number of P=O bond. In contrast with silicate glass in which there is only four-fold coordinated Si4＋, most probably there coexist [SiO4] tetrahedron and [SiO6] oetahedron in our glasses. Within the range of 0 - 20 mol% SiO2 addition, the stimulated emission cross-section of Era＋ ion only decreases no more than 10%. The Judd-Ofelt intensity parameters of Er3＋, Ω2 does not change greatly, but Ω4 and Ω6 decrease obviously with increasing SiO2 addition, because the bond between Er3＋ and O2- is more strongly eovalently bonded.     

激光单分子探测技术的研究

文中介绍利用激光激发分子荧光的方法探测液体中单个染料分子的新技术，以及作者自行设计和研制的激光单分子探测谱仪。通过探测“光子爆发”，把单个染料分子的荧光同很强的背景杂散光区别开来。进一步用８２ＭＨｚ高重复频率的锁模激光器和时间门符合技术，成功地消除了Ｒａｍａｎ散射光。目前该谱仪达到的检测限为灵敏区内仅有～７个Ｒ６Ｇ分子。     

����ͨ���豸��ר�ó������X�ź����ݲɼ��������

采用了通用高速A/D采集器采集信号数据,用软件的方法开发出了具备多道能谱脉冲识别和计数分析能力的软件.用此软件实现了每次托卡马克放电后,在较短的时间内从庞大的原始采集数据中提取出能谱脉冲数据,计算和显示能谱图,这为下一步测量电子温度打下了基础,并同时实现了数据共享.     

Generation and control of Greenberger-Horne-Zeilinger entanglement in superconducting circuits

Going beyond the entanglement of microscopic objects (such as photons, spins, and ions), here we propose an efficient approach to produce and control the quantum entanglement of three macroscopic coupled superconducting qubits. By conditionally rotating, one by one, selected Josephson-charge qubits, we show that their Greenberger-Horne-Zeilinger (GHZ) entangled states can be deterministically generated. The existence of GHZ correlations between these qubits could be experimentally demonstrated by effective single-qubit operations followed by high-fidelity single-shot readouts. The possibility of using the prepared GHZ correlations to test the macroscopic conflict between the noncommutativity of quantum mechanics and the commutativity of classical physics is also discussed.