12 W high power InGaAsP/AlGaInP 755 nm quantum well laser

High power laser diodes(LDs) with a lasing wavelength between 700 and 780 nm have great potential in various medical uses. Here, we report our recent efforts in developing an InGaAsP/AlGaInP-based commercial high power edge-emitting LD, which has 755 nm emission peak with a world-record continuous wave output power of 12.7 W, the highest reported so far. The lack of Al atoms in the active region significantly lowers the chance of catastrophic optical damage during high power laser operation. Meanwhile, with an accumulated 3800 h running time, our ongoing aging tests reveal excellent reliability of our devices.     

中红外下半导体掺杂调制的表面等离子体透射增强效应

理论研究了平面电磁波通过n型重掺GaAs薄膜的透射谱.当GaAs薄膜两表面刻上亚波长的周期性沟槽结构时,透射谱在中红外波段出现了异常的透射增强现象.把这一现象归因于表面等离子体模式和波导模式的耦合.通过优化结构参数可以得到最大的透射效率.此外,发现随着掺杂浓度的升高,透射谱线中的透射峰逐渐向高频方向移动,最优化后透射峰值随掺杂浓度的升高而逐渐降低.这是由于掺杂浓度的改变,导致了不同的等离子体频率和电子碰撞频率,从而影响了激发模式和薄膜对电磁波的吸收. 关键词： 表面等离子体 掺杂半导体 增强透射 掺杂调制     

表面等离子体调制单模面发射激光器的研究

对单模面发射半导体激光器的研究随着其应用的不断扩展而引起了人们的广泛的重视,应用多种方法可以提高其输出功率并改善其模式抑制比.利用金属表面等离子体纳米结构调制的方法可以获得单模面发射激光器输出功率的提高,理论计算表明这种方法增强效应可达近50%. 关键词： 表面等离子体 单模面发射激光器 模式选择     

Effective absorption enhancement in small molecule organic solar cells using trapezoid gratings

We demonstrate that the optical absorption is enhanced in small molecule organic solar cells by using a trapezoid grating structure. The enhanced absorption is mainly attributed to both waveguide modes and surface plasmon modes, which is simulated by using finite-difference time-domain method. The simulated results show that the surface plasmon along the semitransparent metallic Ag anode is excited by introducing the periodical trapezoid gratings, which induce the increase of high intensity field in the donor layer. Meanwhile, the waveguide modes result in a high intensity field in acceptor layer. The increase of field improves the absorption of organic solar cells significantly, which is demonstrated by simulating the electrical properties. The simulated results also show that the short-circuit current is increased by 31% in an optimized device, which is supported by the experimental measurement. Experimental result shows that the power conversion efficiency of the grating sample is increased by 7.7%.     

表面等离子激元调制的亚波长束斑半导体激光器

近场有源探针可以解决近场光学扫描显微镜等应用中对高亮度和高光功率的需求.提出一种制备具有表面等离子激元结构的微纳束斑的半导体激光器的设计方案.模拟分析表明,此激光器在3.5 μm的远场仍然可以获得小于波长的束斑,并且其输出功率密度与没有表面激元结构的激光器比较提高近30倍.     

12 W高功率高可靠性915 nm半导体激光器设计与制作

本文设计并制作了一种高效率、高可靠性的915 nm半导体激光器。半导体激光器是光纤激光器的关键部件,为了最大限度地提高器件的电光转换效率,在设计上采用双非对称大光腔波导结构,同时对量子阱结构、波导结构、掺杂以及器件结构进行了系统优化。器件模拟表明,在25℃环境温度下,器件的最高电光转换效率达到67%。采用金属有机气相沉积(MOCVD)法进行材料生长,随后制备了发光区域宽度为95μm、腔长为4.8 mm的激光芯片。测试表明,封装后器件的效率以及其它参数指标达到国际先进水平,在室温下阈值电流为1 A,斜率效率为1.18 W/A,最高电光转换效率达66.5%,输出功率12 W时,电光转换效率达到64.3%,测试结果与器件理论模拟高度吻合。经过约6 000 h的寿命加速测试,器件功率没有出现衰减,表明制作的高功率915 nm激光芯片具有很高的可靠性。