激光二极管端面纵向泵浦Nd:YVO_4激光器的热效应研究

针对激光二极管端面纵向泵浦Nd:YVO4激光器,本文理论和实验详细研究了Nd:YVO4晶体的热透镜效应。在激光二极管的中心波长分别为808nm和880nm及分别采用单端端面纵向泵浦和双端端面纵向泵浦结构情况下,实验测量了Nd:YVO4晶体的热透镜焦距,实验结果和理论预测基本吻合。同时在泵浦功率60W时获得了18.8W的连续基横模激光输出。     

量子光学实验中宽带低噪声光电探测器的研制

针对量子光学实验的特殊要求,通过设计优化宽带低噪声放大电路,研制出宽带低噪声光电探测器.我们重点分析了影响光电探测器增益、带宽和噪声的因素,通过选择合适的光电二极管、取样电阻、反馈电阻和输出电容,获得了宽带低噪声光电探测器.该光电探测器的带宽为2～50 MHz,能够用于输入功率达15 mW光场的噪声测量,适用于包括平衡零拍探测、差拍探测等量子光学实验.考虑到在量子光学实验中需要一对平衡的光电探测器,我们制作了一对2 MHz～31 MHz带宽内共模抑制比大于30 dB的平衡光电探测器,并用于1064 nm激光和1550 nm激光的强度噪声测量和散粒噪声基准的校准.     

Low noise, continuous-wave single-frequency 1.5-μm laser generated by a singly resonant optical parametric oscillator

We report a low noise continuous-wave (CW) single-frequency 1.5-μm laser source obtained by a singly resonant optical parametric oscillator (SRO) based on periodically poled lithium niobate (PPLN). The SRO was pumped by a CW single-frequency Nd:YVO₄ laser at 1.06 μm. The 1.02 W of CW single-frequency signal laser at 1.5 μm was obtained at pump power of 6 W. At the output power of around 0.75 W, the power stability was better than ±1.5% and no mode-hopping was observed in 30 min and frequency stability was better than 8.5 MHz in 1 min. The signal wavelength could be tuned from 1.57 to 1.59 μm by varying the PPLN temperature. The 1.5-μm laser exhibits low noise characteristics, the intensity noise of the laser reaches the shot noise limit (SNL) at an analysis frequency of 4 MHz and the phase noise is less than 1 dB above the SNL at analysis frequencies above 10 MHz.     

Continuous-wave, single-frequency intracavity singly resonant optical parametric oscillator at 1.5-μm wavelength

We present a 1.5μm continuous-wave （CW） single-frequency intracavity singly resonant optical parametric oscillator （SRO） based on periodically poled lithium niobate （PPLN）. The SRO is placed inside the ring cavity of a single-frequency 1.06μm Nd：YVO4 laser pumped by a laser diode. The device delivers a maximum single-frequency output power of 310 mW at a resonant signal wavelength of 1.57 μm. The signal wave could be tuned from 1.57 to 1.59 μm by temperature tuning of PPLN crystal over the range of 130 - 170℃.     

邯钢的“盒子”

无论是业绩还是规模，邯郸钢铁都不是一家惹人瞩目的公司，但其在金融工具的运用上却创造了“数量之最”，回购、送股、欧式权证、换股，在资本的潘多拉盒子中，邯钢不断演义着自己的传奇，可能手法并不经典，但对类似邯钢这样比较传统行业的企业而言，借鉴意义明显。     

激光稳频技术的研究及进展

激光稳频技术广泛应用在量子光学和量子通讯的实验系统中,用于提高激光频率的稳定度或改善光学谐振腔的输出稳定性等。本文综述了基于光学谐振腔共振频率的稳频技术如PDH(Pound-Drever-Hall)稳频技术、Lock-in鉴相稳频技术、Tilt-locking稳频技术的研究进展,并在这些稳频技术的基础上,阐述了新型改进和发展的自动激光稳频技术。     

一种新型分凝分离式混合工质内复叠节流制冷机的实验研究

混合工质节流制冷机正在许多方面获得越来越广泛的应用。文中提出了一种新型分凝分离式内复叠节流制冷循环 ,设计了一种具有内部传热和传质的分凝分离器并用此来代替传统的气液分离器 ;建立了相应的单级油润滑制冷压缩机驱动的实验系统 ,并分别进行了 1 2 0 K和 1 80 K两个温区的实验研究。在 1 30 K时获得了 60 W的制冷量 ;1 35K时获得了 74W的制冷量 ;1 55K时获得了 2 65W的制冷量。