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为了实现光参变放大抽运光源高稳定输出的目的。通过对倍频过程的数值模拟分析,提出倍频中存在“稳定区”的概念,在基频光强一定的条件下(小于倍频晶体破坏阈值),通过非共线双程倍频的方式或串联倍频的方式可有效延长倍频晶体的有效作用长度,保证倍频工作区能够被控制在“稳定区”内,从而实现高稳定高转换效率的倍频输出。实验数据验证了这一结论,实验中,利用非共线双程倍频的方式使得倍频工作区在“稳定区”内,对波动±5.7%的1064 nm高斯脉冲基频光,倍频光波动小于±2%,脉冲形状为高阶高斯脉冲,转换效率大于70%,实验结果表明,倍频光的稳定性指标相对于基频光提高了近3倍。 相似文献
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讨论了入射基频光频谱宽度、两块和频晶体失谐角对KDP晶体Ⅰ/Ⅱ/Ⅱ类角度失谐级联方式的三倍频光功率谱分布的影响,分析了影响三倍频效率的因素。研究结果表明,第二块和频晶体得到的三倍频光的功率谱分布与基频光功率谱分布及失谐角有关,三倍频光频谱宽度近似为基频光的3倍,采用该方案的三倍频可有效抑制由于基频光时间相位调制导致的三倍频光强随时间分布的不均匀,并能有效提高大带宽条件下的三倍频转换效率。同时,采用该方案的三倍频,对级联的两块和频晶体厚度及失谐角调整精度要求不高,在实验上有很大的可操作性。 相似文献
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《中国光学与应用光学文摘》2004,(4)
用磷酸氧铁钾(KTP)作为倍频晶体,对Nd,YAG声光调Q激光的环形腔外腔倍频技术进行了实验和理论的研究,利用最大平均功率sow、声光调Q、输出频率1005 Hz、灯抽运Nd,YAG激光器作为基频光光源,在基频输人功率35W时,获得了大约为31.4%的光一光转换效率的绿光输出。从实验结果分析了环形腔倍频的特性,指出了该方法 相似文献
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通过统计理论和维纳-辛钦定理推导出激光外差探测系统光电流的功率谱函数,分析了光电流谱线分布与激光光源线宽、中频信号频率以及信号光相对本振光传输延迟时间的关系,修正了相关文献中光电流功率谱的理论公式.根据信号与噪声理论建立了激光线宽引起的相位噪声的一维概率分布模型,并据此得到了基于激光波长、探测距离以及激光线宽的极限位移分辨率的数学模型.对光电流的功率谱和外差光学极限位移分辨率进行了相关的数值仿真,结果表明延迟时间与相干时间的关系决定光电流谱线分布的情况.当激光波长为532 nm,激光线宽在1 kHz,探测距离为100 m时,光学极限位移分辨率为0.266 nm,相关文献中的实验数据与理论推导结果相符合. 相似文献
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Coherent beam combining of hybrid phase control in master oscillator-power amplifier configuration 下载免费PDF全文
A novel scalable architecture for coherent beam combining with hybrid phase control involving passive phasing and active phasing in master oscillator-power amplifier configuration is presented. Wide-linewidth mutually injected passive phasing fibre laser arrays serve as master oscillators for the power amplifiers, and the active phasing using stochastic parallel gradient descent algorithm is induced. Wide-linewidth seed laser can suppress the stimulated Brillouin scattering effectively and improve the output power of the fibre laser amplifier, while hybrid phase control provides a robust way for in-phase mode coherent beam combining simultaneously. Experiment is performed by active phasing fibre laser amplifiers with passive phasing fibre ring laser array seed lasers. Power encircled in the main-lobe increases1.57 times and long-exposure fringe contrast is obtained to be 78% when the system evolves from passive phasing to hybrid phasing. 相似文献
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X. L. Wang P. Zhou Y. X. Ma H. T. Ma X. J. Xu Z. J. Liu Y. J. Zhao 《Laser Physics》2010,20(6):1453-1458
We demonstrate a scalable architecture for coherent combining of all-fiber pulsed lasers with hybrid phase control involving
passive phasing and active phasing for the first time. Synchronized and passive phased pulsed laser array is built by intra-activity
phase modulation. Active phase control on the passive phased pulsed laser array using stochastic parallel gradient descent
algorithm provides stable in-phase coherent beam combining pattern in a turbulent atmosphere. The fringe visibility is increased
from 0 two 0.43 and the power encircled in the main-lobe is 1.616 times increased when the system evolves from passive phasing
to hybrid phasing. The architecture can be easily scaled up to high power by increasing power of each individual laser, number
of laser elements and introduction of power amplifiers, which will lead a promising way for scaleable high power coherent
beam combining of pulsed lasers. 相似文献
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G. Ya. Zelikina M. B. Kiseleva M. V. Buturlimova A. P. Burtsev 《Optics and Spectroscopy》2002,92(2):214-220
Application of coherent interaction of laser light with a focused ultrasonic wave to the technique of acoustooptic visualization in multiple-scattering media is discussed. By analyzing spatial distribution of the optical radiation modulated by ultrasound (the photocurrent at ultrasonic frequency), images of large-sized inhomogeneities embedded into the scattering medium have been obtained. A light-absorbing half-plane and a square with sides of 5 mm were used as the inhomogeneities. The visualization was performed under optimal conditions for measuring the alternating photocurrent calculated for the proposed model of coherent interaction between the laser and acoustic beams (the Raman-Nath diffraction). The alternating current at the ultrasonic frequency was obtained as a result of mixing the waves of the diffraction fields on the detector’s photocathode. All experimental values were obtained from a single measurement without averaging the alternating photocurrent at the ultrasonic frequency of 3 MHz, with the scattering parameter varying up to μL≤37.5, where μ is the extinction coefficient and L is the thickness of the scattering medium along the laser beam axis. The measured quantities varied in the course of the measurements by more than 10 orders of magnitude. 相似文献
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C. C. Santos I. Guedes J. P. Siqueira L. Misoguti S. C. Zilio L. A. Boatner 《Applied physics. B, Lasers and optics》2010,99(3):559-563
In a laser coherent combination, the phase detection and control is the most critical. Using the beat frequency method, consistence
of the phase in output beams can be ensured through real-time detection and correction for the phase change. Phase noises
are controlled by a liquid crystal phase modulator. At the same time, the liquid crystal polarization controller is used to
make the polarization state stable, which is good for the improvement of the combining efficiency. The wave length of the
main oscillation laser is 532 nm. The output power of laser can be adjusted continuously from 0 to 6 W. The shifted frequency
of the system is 40 MHz. The accuracy for phase control is superior to λ/70 RMS. In the process of closed-loop control, using the liquid crystal phase and polarization controller, a better signal
phase correction of optical path has been achieved for the coherent combination of high power laser arrays. 相似文献
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在主动相位控制相干合成中,常用的光纤激光主动相位控制方法主要有外差法、多抖动法和随机并行梯度下降算法等. 基于多抖动法和外差法的原理,提出了一种新型的基于相位调制-解调的相位检测与控制方法. 该方法利用周期信号对参考光进行相位调制,将调制后的参考光与待检测信号光进行相干检测,通过对相干光强信号和相位调制信号的融合处理,实现相位噪声的检测和控制. 对该方法进行了数值模拟和实验研究. 实验结果表明,对于频率为2 kHz,噪声范围为[0,2π)的正弦噪声,相位检测精度优于λ/50,控制精度可达
关键词:
光纤激光
相干合成
相位噪声检测
调制-解调 相似文献
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A technique is presented for determining the frequency modulation transfer function of a laser. The method is based on a Mach–Zehnder interferometer, with a significant difference in the optical path lengths of the two arms. A frequency-modulated laser beam incident on the interferometer produces a phase-modulated photocurrent signal with an effective modulation index that is related to the amplitude of the optical frequency modulation. Techniques for determining both the amplitude and the phase of the optical frequency modulation from the photocurrent signal are described. 相似文献
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We present the phase control of photon correlations in a driven four-level system in the double lambda configuration. The strong correlation and the anticorrelation are. obtained when the collective phase of four applied laser fields is varied. The coherent control is based on the phase-dependent coherent population trapping (CPT). The strong correlation occurs when the system operates near CPT, while the anticorrelation occurs when the system is far away from CPT. 相似文献