共查询到20条相似文献,搜索用时 11 毫秒
1.
A method for increasing the output power of a phase conjugated oscillator (PCO) by using two stimulated-Brillouin-scattering (SBS) cells is described. The average power has been more than doubled and the peak power has been increased by twenty times compared to the single-SBS-cell PCO. Near unity beam quality has been measured. 相似文献
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A new method based on the general theory of amplitude-phase retrieval is proposed for designing the diffractive phase elements (DPEs) used in the laser cavity that can produce the desired mode with the specified shape of beam. Simulation results show that the laser cavity with the designed DPEs can successfully generate uniform square and triangle ring patterns. The loss of these fundamental modes is negligibly small and the separation of adjacent transverse modes is large enough to discriminate the fundamental mode from the higher-order modes. 相似文献
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A laser interferometric system (LIS) based on oblique incidence and phase shifting technique has been designed for the measurement of gear tooth flank. For a spur involute gear with a module of 2.0, 60 teeth, and a 20-mm facewidth, some critical parameters of the LIS are calculated, the oblique incidence angle is 84.5°, the beam diameter is 20 mm, and the focal length of imaging lens is 100 mm, and the resolution of CCD camera is 1360 × 1024 pixels. To test the capability of the designed LIS, the numerical simulation is done for the LIS. The actual LIS is built on an optical platform and the experiment is carried out. Both interference fringe patterns from the numerical simulation and the actual experiment are good and coincident with each other, which show the designed LIS is feasible. 相似文献
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Dicke模型中的量子相变在三十多年前已被预言,该模型描述的是N个二能级原子与单模腔场集体耦合的系统.在标准Dicke模型的基础上加入原子光的非线性相互作用和含时外场驱动,使用含时幺正变换和Holstein-Primafoff变换方法从理论上推导出基态能量表达式.并且给出了丰富的相图,而且这些性质最近已有文献从实验上验证.本文主要呈现了非线性相互作用和外场驱动对量子相变的影响. 相似文献
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A polynomial approximation for the scattering wavefunction of an arbitrary spherically symmetric potential 下载免费PDF全文
A new variational approach is proposed to calculate scattering phase shifts.In this approach,the variational parameter is contained not explicitly in the trial function but in the boundary conditions that the scattering wavefunction should satisfy.It was found that a high accuracy could be reached.Furthermore,the scattering wavefunction appears as a polynomial of finite orders in the interior region.This expression is convenient for applications. 相似文献
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理论分析了共振无源腔对飞秒脉冲激光的强度和相位噪声的转化模型,分析表明,通过测量无源腔透射场或者反射场相对于输入场强度噪声的变化,可以间接得到输入场飞秒脉冲激光的相位噪声.在此基础上设计了精细度约为1500、自由光谱区为75 MHz的八镜环形共振无源腔,并测量了钛宝石锁模激光经过该共振无源腔后透射场和反射场强度噪声的变化.实验观察到,飞秒脉冲激光经过无源腔透射后,强度噪声特性得到较好改善,在探测频率2 MHz附近达到散粒噪声极限.同时,结合共振无源腔对激光强度和相位噪声的转化模型,间接给出了钛宝石锁模激光的相位噪声及无源腔对相位噪声的有效抑制作用. 相似文献
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Gray Malcolm B. McCLELLAND David E. Barton Mark Kawamura Seiji 《Optical and Quantum Electronics》1999,31(5-7):571-582
A small Michelson interferometer has been configured as a tracking mirror displacement sensor in order to achieve both large dynamic range (2.1 mm) and excellent sensitivity
across a broad frequency range (6Hz–3 kHz). The interferometer is illuminated by a simple LED, uses broadband, non-polarising beamsplitters and contains no lensing optics. A DC-coupled balanced detector provides an error signal that is used to position the tracking mirror of the Michelson interferometer so as to maintain an interferometer operating position close to the centre of a particular fringe. The total interferometric sensor provides a small, simple and cost-effective means of achieving high-resolution displacement measurements. 相似文献
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V. N. Belyi N. S. Kazak A. G. Mashchenko B. B. Sevruk 《Journal of Applied Spectroscopy》1999,66(2):187-195
The conditions for collinear phase matching in the parametric generation of light in arbitrary directions of a biaxial KTP
crystal pumped by an Nd:YAG laser were investigated with the use of invariant expressions for the refractive indices of isonormal
waves. The tuning curves, effective nonlinear coefficients, spectral and angular phase-matching widths were calculated.
B. I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, 68, F. Skorina Ave., Minsk, 220072. Translated
from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 2, pp. 177–184, March–April, 1999. 相似文献
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A technique for frequency stabilization of an internal mirror He-Ne laser using phase sensitive detection without cavity length
modulation is suggested. The orthogonally plane polarized modes are separated and then convered into two photoelectric signals
using two photodetectors. The photoelectric signals are switched alternately so as to generate a square wave, whose amplitude
is proportional to the intensity difference between the two orthogonal polarizations. A lock-in amplifier is used to detect
this square wave, with the switching frequency as reference. The phase detected signal is used for thermal stabilization of
the laser. The frequency stability of 5 × 10−9 was obtained with an integration time of 1 s. 相似文献
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Zun-Jiang Zhang 《Optics & Laser Technology》1988,20(6):321-322
An alignment technique for a ring laser cavity is presented which is suitable for a resonator into which auxillary laser beams cannot pass. 相似文献
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Based on equations for the evolution of the polarization density matrix for laser emission, we have shown that when a laser
with an anisotropic cavity is turned on in a magnetic field higher than some critical value, we will observe a new optical
effect: pulsations between the polarized and completely unpolarized states of the laser emission. In a magnetic field much
higher than the critical value, practically complete suppression of polarization occurs, which may serve as a method for obtaining
unpolarized laser emission.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 1, pp. 134–142, January–February, 2008. 相似文献
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理论研究和数值模拟研究表明激光在等离子体中诱导的等离子体密度调制可以起类似布拉格反射镜的作用,使得后面的入射光在等离子体平均密度远低于临界密度的区域就对入射光产生相位反射.相位反射的发生会影响激光在等离子体中的传播,例如激光在等离子体中相对传播时会出现激光场空洞现象.进一步的理论和数值模拟研究表明,相位反射持续发生的时间以及反射率的高低与等离子体的密度、等离子体区域的长度、激光强度以及脉宽等因素密切相关,这些都会对激光在等离子体中的传输产生影响.
关键词:
相位反射
密度调制
激光等离子体
粒子模拟 相似文献
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A. P. Gavrilyuk I. V. Krasnov S. P. Polyutov N. Ya. Shaparev 《Russian Physics Journal》1999,42(8):744-751
The results obtained by the authors in studies of the mechanical action of resonance laser light on gas and plasma are briefly
reviewed.
L. V. Kirenskii Institute of Physics of the Siberian Branch of the Russian Academy of Sciences; Institute of Computational
Modeling of the Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii,
Fizika, No. 8, pp. 96–105, August, 1999. 相似文献
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在一种猝发高重频的X射线自由电子激光(XFEL)装置中,由于受到光阴极注入器内补偿螺线管与电子枪之间特殊结构的限制,阴极附近电场与磁场为叠加状态。实验中需要对阴极热发射度进行测量,而测量热发射度常用的螺线管扫描法基于几何发射度不变的前提,无法直接应用于电磁场叠加的结构。针对这一问题,考虑到归一化过程可以剔除电场对发射度的影响,基于此,研究归一化相空间中应用的螺线管扫描法,并通过仿真计算与分析,最终证明该方法适用于电磁叠加场中阴极热发射度的测量。 相似文献