共查询到18条相似文献,搜索用时 140 毫秒
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首次提出了菱形形位相元结构的随机位相板,用衍射理论分析了经这种随机位相板变换后的激光在远场的光斑特性。结果表明其能量利用率高于其它随机位相板用面阵CCD记录的远场光斑,经计算机处理后得到的光斑包络与数值计算结果一致。 相似文献
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激光光强分布测量中面阵CCD信号畸变的校正 总被引:1,自引:0,他引:1
当面阵CCD用于激光能量空间分布测量时,由于CCD探测器光电响应非线性、光电响应非均匀性等因素影响,必然使信号产生畸变。本文通过理论分析与实验对畸变进行了校正,收到了良好的效果。 相似文献
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基于热声效应,对基底厚度小于热渗透深度的石墨烯薄膜发声器进行理论和仿真研究。首先,利用石墨烯薄膜发声器的热功率平衡方程与气体中的热弹性耦合线性方程组推导出了石墨烯薄膜发声器的近/远场声压表达式。将理论计算结果与实验测试值进行对比,二者吻合良好,验证了理论模型的正确性。然后,利用仿真软件对石墨烯薄膜的近远场声压值进行了仿真计算,并将仿真值与理论值进行对比,二者有良好的一致性,验证了仿真计算方法的有效性。研究表明,石墨烯薄膜发声器的远声场为球面波,近声场近似为平面波。在远场低频段,声压级随输出声频率的增加而缓慢增大;在近场高频段,声压级几乎不受输出声频率的影响。研究结果为基底厚度小于热渗透深度情形下的热致发声器提供了理论计算和分析方法,对石墨烯薄膜声源器件的实验研究具有指导意义。 相似文献
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用Hartmann—Shack传感器测量激光束的波前相位 总被引:7,自引:2,他引:5
Hartmann-Shack传感器已经用于自适应光学系统。它可以同时探测出一束光的振幅和相位信息。通过一个位置传感器,比如CCD,它就可以成为一种对光学系统和光束的静态和动态质量诊断的有力工具。从H-S波前传感器的输出(波前斜率和近场强度分布),就可以推算出远场特点,如PSF和OFT。本文将介绍波前重构的理论分析和远场特征评估。同时也给出了光束质量的静态和动态的测量结果。 相似文献
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激光表面熔凝温度场计算 总被引:8,自引:0,他引:8
本文介绍了一种简单的半解析法-热源函数法在Cu-Mn和Al-Cu合金激光表面快凝熔池温度场计算中的应用,计算结果与实验结果的对比发现两者在中等扫描速度下符合得较好。 相似文献
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激光表面熔凝温度场计算 总被引:1,自引:0,他引:1
本文介绍了一种简单的半解析法—热源函数法在Cu-Mn和Al-Cu合金激光表面快凝熔池温度场计算中的应用,计算结果与实验结果的对比发现两者在中等扫描速度(v≤1m/s)下符合得较好。 相似文献
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Bochum H 《Applied optics》1997,36(15):3349-3356
The theoretical and experimental investigation of field properties of annular waveguide lasers with a Fabry-Perot resonator is presented. Oscillation with high azimuthal mode order leads to an annular intensity distribution in the far field with almost linear dependence of the annular diameter on the mode order. Low-order fields form a distinct focal spot in the far field. A laser device with a discharge area of 6-cm diameter and 53-cm length yields an output power of 600 W. 相似文献
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F I Baida D Van Labeke A Bouhelier T Huser D W Pohl 《Journal of the Optical Society of America. A, Optics, image science, and vision》2001,18(7):1552-1561
With the use of optical near-field techniques, it is now possible to excite or observe surface plasmons with high lateral resolution. A theoretical study is presented of surface plasmon excitation by near-field optical probes and the influence of well-defined structures on surface plasmon propagation and surface plasmon detection in the far field. The generation and the diffraction of the surface plasmon is calculated by using a theoretical scheme founded upon a first-order perturbation expansion of the Rayleigh-Fano method. A very good agreement is obtained between numerical and experimental results. The theoretical tools used should prove a useful guideline for future experiments of nanooptics with surface plasmons. 相似文献
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Experimental and theoretical results for bending of a soft ferromagnetic plate in a transverse magnetic field 总被引:1,自引:0,他引:1
Summary. The results of an experimental and theoretical investigation of the bending behavior of a soft ferromagnetic cantilever beam-plate
in a transverse magnetic field are presented. The theoretical model based on a beam-plate theory for magneto-elastic interactions
in a soft ferromagnetic material predicts the deflection and strain for several values of the magnetic field and the geometrical
parameter. The experiments were conducted on ferritic stainless steel SUS430 in the bore of a superconducting magnet at room
temperature. The experiments show the predicted increase in the deflection and strain with increasing magnetic field. The
theoretical results agree very well with the experimental data.
Received April 15, 2002
Published online: May 8, 2003 相似文献
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B. Grzegorzewski 《Journal of Modern Optics》2013,60(10):1351-1364
Abstract The fluctuations of fringe-pattern intensity are studied theoretically by means of Young's interference experiment applied to speckle. We have studied the fluctuations generated by partially developed Gaussian speckle produced in the far field. The formula for the average contrast of the fringe-pattern intensity is derived and the characteristic values of the contrast fringes are discussed. The theoretical results are compared with experimental data. 相似文献
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Xu YL 《Applied optics》1997,36(36):9496-9508
In electromagnetic multisphere-scattering calculations the reexpansion method for seeking a single-field representation of the total scattered field is found impracticable because of severe numerical problems. We present a simple single-field expansion of the total scattered far field based on an asymptotic form of vector translational addition theorems. With this asymptotic expansion of the far field, we derive analytical expressions for the scattering properties of an arbitrary aggregate of spheres. Resulting formulas are free from numerical problems in practical applications. Theoretical predictions from this far-field solution for various aggregates of spheres that we tested agree favorably with laboratory microwave scattering measurements. Some numerical results are presented and compared with experimental data. 相似文献
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《Journal of Modern Optics》2013,60(10):1373-1396
Some expressions for the e.m. field diffracted by an absorbing circular cylinder of large radius in the Fresnel region are developed. Until recently results were available only for the far field of ‘good conductors’. The derived equations agree with Young's theory of diffraction since the diffracted field may be expressed as two cylindrical waves which seem to arise from the two ‘edges’ of the cylinder. Numerical calculations are also presented and compared with previous experimental results. 相似文献
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The theoretical analysis and experimental demonstration of phase modulation spectroscopy employing an all-fiber piezoelectric transducer modulator for a fiber ring resonator fiber-optic gyroscope is presented for the first time as far as we know. The results support the feasibility of such a technique as a rotation detection scheme for a resonator fiber-optic gyroscope. 相似文献