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High-frequency pulsed AlGaAs semiconductor lasers with pulse durations in the nanosecond range show a distinctive enhancement of the time-averaged optical output power compared with continuous-wave mode operation. Hence, the signal-to-noise ratio is drastically increased in connection with fast Si-Avalanche photodetectors that show a maximum spectral sensitivity in the emission range of AlGaAs lasers. The emission behaviour and the application of sequential and phase- synchronized pulsed laser diodes in a multi-component laser Doppler anemometer with only one receiver, one signal processing chain and identical wavelength for all components, are outlined. 相似文献
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高能激光系统中的物理问题 总被引:5,自引:0,他引:5
文章讨论了高能激光系统存在的一些物理问题,着重分析了高能激光系统能力的物理限制,全系统光束质量控制,光束通道和光学元件热效应的产生和抑制,并报道了相关的模拟实验结果.利用数千瓦的氧碘化学激光器(COIL)系统,研究了激光器输出光束的稳定和净化效果,镜面和镜架热效应及其抑制方法,以及通道介质的热效应及其抑制方法,最后还介绍了全系统光束质量一体化控制的共光路共模式(CPCM)自适应光学校正方法. 相似文献
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J. Oldengarm 《Optics & Laser Technology》1977,9(2):69-71
All-glass rotating diffraction gratings developed for use as beam splitting frequency shifters in laser Doppler anemometers are described. The gratings are produced using etching techniques and can be exposed to high power laser beams. Advantages of using these gratings in optical arrangements are that they are simple to set-up and easy to align. 相似文献
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数值模拟研究了高速气流作用下激光加热金属平板温度场。流体控制方程为三维雷诺平均Navier-Stokes方程,固体控制方程为能量方程,湍流粘性系数求解使用k-两方程模型。采用流固耦合计算方法,使用两相流模型模拟气流对烧蚀物的剥蚀,较完整地模拟了激光辐照金属材料的物理变化过程,计算得到了不同气流速度下金属平板的温度分布以及烧蚀形貌。分别使用两相流方法和动网格方法对高速气流作用下激光对金属板的烧蚀效应进行了计算,结果表明,两相流方法与动网格方法都能较好地模拟高速气流作用下激光加热金属平板的温度响应,由于两相流方法能够较全面地模拟对流换热、熔化与凝固过程以及金属液体在气流冲刷下的动力学过程,因此能获得比动网格方法更为合理的物理图像。 相似文献
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数值模拟研究了高速气流作用下激光加热金属平板温度场。流体控制方程为三维雷诺平均Navier-Stokes方程,固体控制方程为能量方程,湍流粘性系数求解使用k-ε两方程模型。采用流固耦合计算方法,使用两相流模型模拟气流对烧蚀物的剥蚀,较完整地模拟了激光辐照金属材料的物理变化过程,计算得到了不同气流速度下金属平板的温度分布以及烧蚀形貌。分别使用两相流方法和动网格方法对高速气流作用下激光对金属板的烧蚀效应进行了计算,结果表明,两相流方法与动网格方法都能较好地模拟高速气流作用下激光加热金属平板的温度响应,由于两相流方法能够较全面地模拟对流换热、熔化与凝固过程以及金属液体在气流冲刷下的动力学过程,因此能获得比动网格方法更为合理的物理图像。 相似文献
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利用脉冲激光进行光速测定 总被引:3,自引:0,他引:3
介绍了利用溴化亚铜激光器输出的脉冲激光通过光纤延时的方法测出光波波包中心所通过的光程及所需时间,从而实现测定光速的实验开设及其设计思想。 相似文献
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Turbulent swirling water flow in a pipe has complex velocity distributions with special measurement problems tor experimental work. Some of these problems are described in the introduction to the paper along with comments on the basic characteristics of turbulent swirling flow.The form of laser Doppler anemometer used is briefly noted, with some special optical features developed to suit this class of flow. Experience during some two years of comprehensive experimentation is then outlined, including comment on the data processing system.Results from experiments with tangentially injected water flow in 50 mm bore pipes up to 60 diameters long are reported, with local measurements of mean velocity and turbulence intensity. The variation of mean velocity components and turbulence intensity with radius and distance along the pipe are discussed with a few comparisons of results obtained from other experimental techniques, e.g. pitot-static probe and hot films.For the particular problem examined here it would have been difficult, if not impossible, to obtain the measurements using a technique other than laser anemometry. 相似文献
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Matt Grupen Paul Sotirelis Steve Wong John Albrecht Robert Bedford Sarah Maley Tom Nelson Bill Siskaninetz 《Optical and Quantum Electronics》2008,40(5-6):349-354
A unique discretization scheme that couples Maxwell’s full wave vector field equations self-consistently with nonlinear charge and energy transport is presented. The scheme is used to simulate laser modulation achieved in a simple electrically pumped quantum well laser diode by dynamically heating the degenerate quantum charge gases with high frequency radiation. 相似文献
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We report upon some experiments done on a continuous-wave argon-ion laser which offers 300 W output power in the visible and 34 W in the ultraviolet region of the spectrum, limited by the degradation of the resonator mirrors. To avoid destruction of the outcoupling mirror, a folded three-mirror instead of a two-mirror cavity was tried, resulting in nearly the same output power. 相似文献
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S. L. Danilishin 《Optics and Spectroscopy》2004,96(5):727-733
A method of enhancing the sensitivity of laser gravitational antennas based on tracking of the velocity of the antenna reflectors instead of conventional tracking of their displacement is considered. This method allows one to overcome the standard quantum detection limit for a weak force. An optical scheme of a gravitational wave detector on the basis of a speed meter is considered. The formulas for the limiting sensitivity of the given scheme taking optical losses into account are obtained. The possibility of realizing the considered measurement method in presently existing laser gravitational antennas is analyzed. 相似文献
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用超高速激光纹影技术测量了Z箍缩等离子体磁重联现象。实验采用超高速光电分幅相机,配合激光纹影技术,测量了XP-1装置上两根金属丝产生的等离子体分布,论证了超高速激光纹影技术研究Z箍缩磁重联现象的可行性。双钨丝实验结果表明,电流加载约10ns后金属丝已有明显膨胀,线性拟合得到平均膨胀速度约8km/s,金属丝内外两侧出现了规则的极有可能是垂直磁场的电热不稳定性扰动,并沿角向高度关联。铝丝负载的实验结果表明,早期的不稳定性波长为0.4mm,电流峰值之后金属丝初始位置仍有大量等离子体,后期的不稳定性波长约1.5mm。这些现象揭示了不稳定性发展的一个主要特征:短波模式受抑制,长波模式将占主导。 相似文献
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用超高速激光纹影技术测量了Z箍缩等离子体磁重联现象。实验采用超高速光电分幅相机,配合激光纹影技术,测量了XP-1装置上两根金属丝产生的等离子体分布,论证了超高速激光纹影技术研究Z箍缩磁重联现象的可行性。双钨丝实验结果表明,电流加载约10 ns后金属丝已有明显膨胀,线性拟合得到平均膨胀速度约8 km/s,金属丝内外两侧出现了规则的极有可能是垂直磁场的电热不稳定性扰动,并沿角向高度关联。铝丝负载的实验结果表明,早期的不稳定性波长为0.4 mm,电流峰值之后金属丝初始位置仍有大量等离子体,后期的不稳定性波长约1.5 mm。这些现象揭示了不稳定性发展的一个主要特征:短波模式受抑制,长波模式将占主导。 相似文献
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Chern-Sheng Lin Jui Tsung Huang Tzu-Chi Wei Mau-Shiun Yeh Der-Chin Chen 《Optics & Laser Technology》2011,43(1):218-225
This study used a high-speed high-resolution line scan CCD, and a Delta motor drive module to provide position feedback in a laser marking system. Based on a novel algorithm, image processing of the high-speed CCD scan was allowed the accurate determination of the laser marking location. This system was calibrated using a template, and a novel 1-D calibration model of the line scan CCD was developed. The relevant position of each IC in the tray was obtained based on the calibration algorithm. Gain and offset calibration, sub-pixel calculation, and normalized checks were performed in this automatic optical inspection system. The total processing time for laser correction marking, scanning and identification was about 2~2.5 s, the positioning accuracy was×9 μm, and the industrial specification and process capability index Cpk reached over 1.2. 相似文献
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《Optics Communications》1987,62(1):29-31
Employing an unstable resonator in a nitrogen laser with a short channel and high output energy, spatially coherent ultraviolet radiation with radiance 6.5×1012 W/sr and output energies ranging from 0.1-0.9 mJ for different geometrical magnifications of the resonator are obtained. These figures are the highest reported for a single channel nitrogen laser. 相似文献
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In this work we present the behavior of a very compact XeCl laser system.Itconsists of an oscillator and an amplifier,both with lateral UV-preionization.Both dischargeelectrodes are contained in a single vessel.An unstable optical cavity is applied to the oscilla-tor.An output beam of 105 mJ,with a brightness of 5.5× 10~(l3)Wcm~(-2)Sr~(-1) and with a diver-gence of 0.9 mrad has been obtained. 相似文献