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报道了一种结构紧凑的垂直外腔面发射激光器(Vertical-External-Cavity Surface-Emitting Laser,VECSEL)及其双波长调控。通过调控泵浦光功率,实现了VECSEL输出的两个激光波长之间的相互转换,双波长的间隔接近50 nm。VECSEL的输出功率曲线呈现明显的两次翻转,翻转点对应了激射波长的转换。这是由于泵浦功率变化改变了增益芯片内部的温度,进而通过热调谐使得发光区增益峰值被调谐到腔模的不同位置。在0℃时,每个激射波长的最大输出功率都在1.5 W以上。随着泵浦功率的改变,激射波长可以在950 nm和1000 nm之间切换,同时还可以在1.5 W以上的功率水平下实现双波长同时激射。这种可切换波长及双波长同时激射的VECSEL器件在光调制、差频等领域有较大应用潜力。 相似文献
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高功率650~660 nm波段激光器在可见光光电对抗领域具有重要作用,目前该波段光源由固体激光器通过半导体激光器泵浦并倍频输出,输出功率高、光束质量近衍射极限,但转换效率低。半导体激光器的转换效率高,但输出功率低,需要通过增加激光单元的方法提升功率,并通过激光合束的方式提升光束质量。文中提出外腔光谱合束的650 nm波段半导体激光器结构,通过实验验证可实现连续功率为7.3 W、光谱线宽为6.45 nm、电光转换效率为23.4%的650 nm波段激光输出,光束质量为M_(X)^(2)=1.95,M_(Y)^(2)=11.11,接近固体激光器,未来通过增加合束的激光单元数量并结合偏振合束可以获得更高功率的650 nm波段激光。 相似文献
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聪明者如夏新,早早地进入手机制造行业,现在虽说不上活得甘甜,但至少优于大部分碟机企业的生存现状。失意者如金正,因为长期找不到新出路, 终至无力回天沦为破产。一正一反两个实例以及行业危局表明,中国碟机企业的生存问题应该提上议事日程。所以,老牌碟机企业万利达日前宣布切入液晶彩电市场之举,再次显现了碟机企业转型 相似文献
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本文对具有多非线性控制项的控制系统,得到了绝对稳定的一般性充要条件,并对其特殊情况给出了构造性充要条件. 相似文献
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A new cellular automata model of traffic flow with negative exponential weighted look-ahead potential 下载免费PDF全文
With the development of traffic systems, some issues such as traffic jams become more and more serious. Efficient traffic flow theory is needed to guide the overall controlling, organizing and management of traffic systems. On the basis of the cellular automata model and the traffic flow model with look-ahead potential, a new cellular automata traffic flow model with negative exponential weighted look-ahead potential is presented in this paper. By introducing the negative exponential weighting coefficient into the look-ahead potential and endowing the potential of vehicles closer to the driver with a greater coefficient, the modeling process is more suitable for the driver's random decision-making process which is based on the traffic environment that the driver is facing. The fundamental diagrams for different weighting parameters are obtained by using numerical simulations which show that the negative exponential weighting coefficient has an obvious effect on high density traffic flux. The complex high density non-linear traffic behavior is also reproduced by numerical simulations. 相似文献
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We study the effects of electron-phonon interaction on the electron ground state in a symmetric triangular quantum well, and calculate the ground state energy of an electron in the GaAs/Al0.96Ga0.04As triangular quantum well including the effects of the interaction between electrons and confined LO phonons by using a modified Lee-Low-Pines variational method. The electron wavefunction in the triangular well is chosen as the Airy function. The numerical results are given and discussed. 相似文献
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NECESSARYANDSUFFICIENTCRITERIAFORABSOLUTESTABILITYOFTHEDIRECTCONTROLSYSTEMZhangJi-ye(张继业);ShuZhong-zhou(舒仲周)(DepartmentofEngi... 相似文献
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NECESSARY AND SUFFICIENT CONDITIONS FOR THE ABSOLUTE STABILITY OF DISCRETE TYPE LURIE CONTROL SYSTEM
张继业 《应用数学和力学(英文版)》1995,(5)
NECESSARYANDSUFFICIENTCONDITIONSFORTHEABSOLUTESTABILITYOFDISCRETETYPELURIECONTROLSYSTEMZhangJiye(张继业)(ReceivedOct.5.1994;Comm... 相似文献