LD泵浦Nd：YVO_4激光器的基横模、高重复频率声光调Q

用国产激光二极管，实现了连续泵浦Ｎｄ：ＹＶＯ４激光器声光调Ｑ．以及单纵模预激光调Ｑ输出。在较小的泵浦功率下．得到了２．４％的光－光转换效率，斜效率为１２．５％，脉冲宽度为６０ｎｓ，激光为基横模输出．将实验结果与ＬＤ泵浦Ｎｄ：ＹＡＧ激光器进行了比较．     

激光二极管泵浦室温Tm,Ho:YLF微片激光器的实验研究

对激光二极管泵浦Tm，Ho：YLF平平腔微片激光器进行了实验研究。在室温下获得2μm连续激光输出，最大输出功率343mw，最大光-光效率为16．8％，斜率效率为21．8％。讨论了激光晶体的热效应以及激光模半径与泵浦光斑半径匹配对激光输出功率和输出光束质量的影响。     

连续输出62．5mW的LD泵浦Nd：YAG微片激光器

实现了ＬＤ泵浦Ｎｄ：ＹＡＧ微片激光器的室温运转，当泵浦功率为３４０ｍＷ时，１．０６μｍ激光的ＣＷ输出功率为６２．５ｍＷ，总的光－光效率为１８％。本文简述了实验装置、结果，研究了微片激光器的一些输出特性。     

激光二极管泵浦Nd：YVO_4晶体的激光特性

报道了用激光二极管纵向泵浦掺钕钒酸钇晶体的激光实验结果。当输入功率为３２０ｍｗ时，激光输出为７８．８ｍＷ，光一光转换效率为２４．６％。     

激光二极管泵浦高效Nd：YVO_4激光器特性研究

报道了激光二极管泵浦高效Ｎｄ：ＹＶＯ４激光器输出功率及波长特性的研究。基频光输出２３０ｍＷ，光－光转换效率为４５％。对激光输出波长和泵浦功率的关系进行了研究，发现激光器的输出波长随泵浦功率的平均变化率约为１．０５×１０－３ｎｍ／ｍＷ。利用ＫＴＰ腔内倍频获得２９．８ｍＷ的绿光输出，光－光转换效率为１２．４％。     

高效高重复率Q－YAG倍频脉冲激光器泵浦钛宝石激光器输出特性的研究

用国产声光调Ｑ－ＹＡＧ倍频脉冲激光器泵浦钛宝石激光器，从理论和实验上研究了该激光器的输出特性，泵浦功率为８．１Ｗ时获得了２．０８Ｗ的钛宝石光脉冲输出，稳定的斜度效率为３０％。     

二极管端泵浦Nd：YAG连续激光器

我们研制了一台二极管连续端泵浦的Ｎｄ：ＹＡＧ激光器，用国产激光二极管作泵浦源，泵浦激光波长为０．８０８μｍ。激光介质为φ５×５ｍｍ的Ｎｄ：ＹＡＧ棒，输出激光波长为１．０６μｍ，用ＣＣＤ相机和图象处理系统记录和分析激光光斑，得到激光横模为ＴＥＭ００模，当输入谐振腔的泵浦功率为２２５ｍＷ时，输出连续激光功率最高达７６．４ｍＷ，光－光转移效率为３３．９％，电光斜效率达到９．１％，并做了腔外倍频实验。     

LD纵向泵浦腔内倍频激光器腔参数的选择

从理论上研究了在一定长ＫＴＰ情况下ＬＤ纵向泵浦Ｎｄ：ＹＶＯ４／ＫＴＰ腔内倍频激光器的绿光输出与腔长、输出镜曲率半径及泵浦光斑半径等参数的关系。根据分析选择了一组实验参数，在入射泵浦功率为６６８．７ｍｗ时获得了１５３．９ｍｗ的绿光输出，光一光转换效率为２３％。将实验结果与理论计算值进行了比较，两者符合较好。     

四价铬镁橄榄石激光器特性研究

文中简要介绍了掺四价铬镁橄榄石（Cr4 ：Mg2SiO4）晶体特性。对实用晶体的吸收特性与晶体取向的关系进行了实验测试。用1．06μm调QYAG激光泵浦，研究了三种不同透过率非色腔的输出特性，并就泵浦光的偏振方向对输出特性的影响做了实验研究，得到输出能量大于29mJ的结果，光一光转换效率达14．5％。     

1.535μmEr：Yb磷酸盐玻璃薄片连续激光器

报道了以９８０ｎｍ钛宝石激光端面泵浦室温连续１．５３５μｍＥｒ：Ｙｂ磷酸盐玻璃薄片激光器。实验上研究了９５０－９８８ｎｍ泵浦波长范围内激光输出特性，结果表明，９７５ｎｍ为最佳泵浦波长。在９７５ｎｍ泵浦下，实现了５ｍＷ低阈值起振和２１％的光－光转换效率；最大单频线偏振输出功率达２２ｍＷ。同时，观察并分析了高泵浦条件下输出激光的偏振与纵横性质，以及由泵浦吸收饱和而引起的输出功率饱和效应。     

W波段准光模式变换器的设计

准光模式变换器是大功率输出回旋管的关键部件.采用高转换效率的准光模式变换器可以横向输出电磁波,增大收集极的尺寸,提高回旋管的输出功率,提高整管效率.该文设计的回旋管内置准光模式变换器由Denisov辐射器天线和四个反射镜组成,输入频率为94GHz,模式为TE_6,2模.采用耦合波理论分析和优化了Denisov辐射器内的场分布,并根据矢量绕射理论编制数值模拟程序计算了各个反射镜上的场分布,其输出功率转换效率达97.2%.利用三维全波仿真软件feko6.0进行对比分析,最后加工所设计的结构并内置于回旋振荡管进行热测实验,结果表明其输出场分布与理论计算结果基本一致.     

声光可调谐滤波器（AOTF）之模分离器的研究及设计

声光可调谐滤波器的设计关键是它的各个模块,包括光波导、模分离器、声波导和叉指换能器的参数设计。采用BPM方法计算了模分离器中对称模和非对称模的相位差,得到了TE模具有100%的转换率,而TM模的转换率为0时所对应的中央耦合部分长度Lc和分叉角θ之间的关系曲线。从该曲线可以得到同时满足TE模叉通和TM模直通条件的Lc和θ。最后,再次利用BPM这一工具,对所设计的模分离器进行了性能分析。     

Photochemically Switchable Interconnected Microcavities for All-Organic Optical Logic Gate

Optical microcavities confine molecular luminescence and transfer it to a far longer distance than the conventional Förster resonant energy transfer process. Such cavity-mediated energy transfer is advantageous for use in optical circuitry. However, to realize all-organic optical circuits, optical gate operation with organic materials is indispensable. Here, all-organic optical gates consisting of polymer whispering gallery mode (WGM) resonators that work as the optical source, drain, and gate, which are interconnected with polymer microfiber, are demonstrated. Photoirradiation of the source sphere, as an optical input, triggers the blue fluorescence that transmits to the gate sphere through the fiber. The fiber interconnection enhances both the light confinement efficiency in the individual spheres and the light transmission efficiency between distant spheres. The gate sphere contains photoisomerizable fluorescent dye that converts, in its closed state, the blue emission into green light, which is again transmitted to the drain sphere through the fiber and lets the sphere emit red light as an output. This optical cascade is switched on and off upon photoisomerization of the dye in the gate sphere. Furthermore, an energy cascade equipped with two gate spheres works as an OR-type logic gate, demonstrating potential utility for the future all-organic and all-optical integrated devices.     

Enhancing extracted electroluminescence from light-emitting electrochemical cells by employing high-refractive-index substrates

Solid-state light-emitting electrochemical cells (LECs) show several advantages over conventional organic light-emitting devices (OLEDs) such as simple device structure compatible with solution processes, low operation voltage and capability of utilizing inert cathode metals. However, device performance of LECs must be improved, e.g. enhancing light extraction, to meet the requirements for practical applications. Among the optical modes trapped in LECs, light trapped in substrate mode is easier to be extracted, e.g., by simply roughing the output surface. Therefore, increasing the percentage of substrate mode is beneficial in improving light extraction. In this work, the contributions of optical modes in LECs employing substrates with various refractive indices are analyzed. Higher-refractive-index substrates are shown to trap more light in the substrates. Smaller refractive index difference between higher-refractive-index substrate and indium tin oxide (ITO) layer also increases the cutoff spectral range of light waveguided in ITO layer. Furthermore, light intensity in surface plasmon mode significantly reduces as the refractive index of the substrate increases. Reducing the percentage of surface plasmon mode facilitates light extraction since it requires more complicated methods for outcoupling light in this mode. With commercially available unpolished sapphire substrates, light output of LECs is enhanced by 56%. When a scattering layer was inserted between ITO and sapphire substrate, more light in substrate mode can be extracted and 71% enhancement in light output is realized. High external quantum efficiency up to 5.5% is consequently obtained in LECs based on a ruthenium complex. Such device efficiency is among the highest reported values for red-emitting LECs and thus confirms that utilizing higher-refractive-index substrates would offer a simple and feasible approach to improve light output of LECs. In comparison to OLEDs, increased EL trapped in substrates of LECs mainly comes from surface plasmon mode rather than waveguide mode.     

大功率LD与多模光纤的直接耦合

将多模光纤末端研磨成圆锥面,与大功率LD进行直接耦合.分析了影响耦合效率的主要因素,提出了在工具显微镜上实现直接耦合的新方法,耦合效率高于50.8%.     

共线声光模式转换效率的分析与计算

利用声表面波共线声光效应的衍射光栅可使波导中导模向泄漏模转换,此现象在光通信在线解复用系统具有潜在应用前景。利用耦合模理论求解这一过程,模式转换效率可以化作声波频率、声光作用长度、波导厚度和声波功率密度的函数,利用数值计算得出结果并给出其关系。由数值计算结果可知,x切质子交换铌酸锂波导模式转换效率最大,适当选择波导长度和声驱动功率密度,其TE0→TMυ转换效率可达90%以上。     

Performance Evaluation of Ethernet Frame Burst Mode in EPON Downstream Link

We apply IEEE 802.3 frame burst mode (FBM) to the Ethernet passive optical network (EPON) downstream link and compare its performance with non‐frame burst mode for various traffic patterns. Although in light traffic loads (ρ<0.5) the efficiency of the FBM mechanism is not significant, it does feature high throughput, small jitter, low queue occupancy, and short queuing delay in optical line terminals under various traffic loads with various numbers of optical network units (ONUs). The FBM performance always approaches that of full‐duplex mode, especially under heavy traffic loads (ρ>0.5). Moreover, an increase in number of ONUs will decrease the burst performance. Our work shows that FBM scheme is very useful for EPON transmission and has low design complexity.     

Very high efficiency solar cell modules

The Very High Efficiency Solar Cell (VHESC) program is developing integrated optical system–PV modules for portable applications that operate at greater than 50% efficiency. We are integrating the optical design with the solar cell design, and have entered previously unoccupied design space. Our approach is driven by proven quantitative models for the solar cell design, the optical design, and the integration of these designs. Optical systems efficiency with an optical efficiency of 93% and solar cell device results under ideal dichroic splitting optics summing to 42·7 ± 2·5% are described. Copyright © 2008 John Wiley & Sons, Ltd.     

投影电视的均匀照明系统设计

分析和设计了用于提高大屏幕投影电视光学性能的均匀照明系统：透镜阵列和积分方棒。基于弧长为1．2mm的超高压水银灯(UHP)．建立嵌套圆筒的体光源模型．给出了两个照明系统的设计方法和用于2．3cm空间光调制器照明系统的设计参数。仿真结果表明,透镜阵列系统实现了均匀性( 4．55％,-5．54％),光能利用率为81％的照明输出;积分方棒系统实现了均匀性( 4．37％,-4．58％),光能利用率为79％的远心照明输出。均能满足投影电视对照明系统的指标要求。     

Estimating the Maximum Attainable Efficiency in Dye‐Sensitized Solar Cells

For an ideal solar cell, a maximum solar‐to‐electrical power conversion efficiency of just over 30% is achievable by harvesting UV to near IR photons up to 1.1 eV. Dye‐sensitized solar cells (DSCs) are, however, not ideal. Here, the electrical and optical losses in the dye‐sensitized system are reviewed, and the main losses in potential from the conversion of an absorbed photon at the optical bandgap of the sensitizer to the open‐circuit voltage generated by the solar cell are specifically highlighted. In the first instance, the maximum power conversion efficiency attainable as a function of optical bandgap of the sensitizer and the “loss‐in‐potential” from the optical bandgap to the open‐circuit voltage is estimated. For the best performing DSCs with current technology, the loss‐in‐potential is ～0.75 eV, which leads to a maximum power‐conversion efficiency of 13.4% with an optical bandgap of 1.48 eV (840 nm absorption onset). Means by which the loss‐in‐potential could be reduced to 0.4 eV are discussed; a maximum efficiency of 20.25% with an optical bandgap of 1.31 eV (940 nm) is possible if this is achieved.