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1.
In this paper, propagation and polarization characteristics of optical waves in arbitrary directions in a biaxial crystal are analyzed, and universal relationships of refractive index dependence on their propagation directions and the principal refractive indices for two perpendicular polarization waves propagating in arbitrarily directions are derived from indicatrix equation. By using these relationships, methods of collinear phase matching (PM) of SHG are developed, and general expressions of the collinear PM angle dependent of the principal indices are given for SHG in arbitrarily directions. The expressions may be used to make optimization design of PM by computer for the SHG and to select optimum PM direction and to raise the SHG conversion efficiencies. 相似文献
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On the basis of the asymmetric velocity tensor introduced we develop an orthogonal representation of wave propagation in anisotropic
magnetic dielectrics. Simple expressions are obtained for the direct dependence of polarization vectors, refractive indices,
and phase and group velocities of isonormal waves in a magnetic dielectric on the vectors of principal velocities. We show
that the presence of magnetic properties is manifested in the optical range in the fact that the velocities of wave propagation
in uniaxial crystals are determined by three main refractive indices, and therefore, both waves except for specific directions
become extraordinary, whereas in biaxial crystals (also because of a large number of parameters) the cones of internal and
external refraction become elliptic.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 5, pp. 597–600, September–October, 1999 相似文献
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双轴晶体主平面上倍频的相位匹配参量 总被引:1,自引:0,他引:1
根据折射率椭球方程及双光轴晶体中光波的传播与偏振特性,分析双轴晶体在主平面内激光倍频相位匹配的特性与方法,导出光波在主平面上传播时倍频的相位失配关系;给出双轴晶体中容许相位匹配倍频的相位匹配角及混频的有效非线性系数deff的表达式。利用可相位匹配的类型、相位匹配角公式和有效非线性系数deff表达式的表,容易对任意一具体晶体在一给定波长求出实际能实现相位匹配的类型或偏振组合,算出相位匹配角,比较不同的相位匹配类型或偏振组合的有效非线性系数,选择最佳的相位匹配类型与方向。从相位失配关系可以计算晶体主平面内倍频的接收角、接收光谱宽度等特性参量。 相似文献
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Plane-parallel biaxial plates as polarization interferometers. Knowing the refractive indices and the directions of the rays inside a birefringent crystal, it is possible to calculate the positions of the images formed, when a non-parallel light beam incides on it.We part from general expressions for images in plane-parallel plates of any type of medium and we use vectorial expressions for the incident and refractive rays and waves in both interfaces.From them, we obtained the interference patterns which are observed when the plate is placed between two crossed polarizers. This experimental device constitutes a polarization interferometer. In order to find the shape of the interference patterns, we superposed the wave's fronts emerging from the images determining, in this way, the phase difference curves of phase constant on a screen. 相似文献
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根据非中心对称双轴晶体中两束基频光与它们产生的二次谐波的折射率曲面的关系及相位匹配条件,分析了和频效应相位匹配曲面的特点,对正常双轴晶体得出了可实现的29种相位匹配曲面拓扑图和存在条件,15种非临界相位匹配类型、存在条件和偏振关系.并用这种理论分析了LAP晶体、KB_5晶体的和频性能. 相似文献
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给出了洛匈棱镜正、反向使用时分束角的精确表达式。从理论上证明,对任意合理的结构角及主折射率值来说,洛匈棱镜反向使用时的分束角小于正向使用时的分束角。研究了在锥光入射条件下洛匈棱镜中的e光和o光的传播方向、折射率、主平面、偏振方向等问题。证明了洛匈棱镜正向使用时第二块晶体中无偏折的光波只含有o光,参考圆圆周上各点光波的主平面相互平行,通过一个检偏器后可以实现消光;洛匈棱镜反向使用时,第二块晶体无偏折的光波同时包含了o光和e光,参考圆圆周上各点光波的主平面沿参考圆的径向,e光和o光的偏振方向分别沿径向和垂直于径向,通过检偏器后形成锥光干涉现象,不能消光。 相似文献
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Considering an interface between two uniaxial birefringent crystals, four reflected and four refracted waves for each incidence direction are obtained. Along this direction can propagate an ordinary wave and an extraordinary wave. Here, we present the analytic expressions for the four critical angles, from which each refracted wave no more exists as propagating wave. We show the variation in these critical angles for different interfaces varying the orientation of the incidence plane with respect to the optical axes. When both principal refractive indices of the second medium are smaller than those of the first medium, then the four critical angles exist for each incidence plane and for any direction of the optical axes. But, when one of the indices has an intermediate value between the values of the indices of the other crystal, we can chose the optical axes directions in such a way that certain critical angles do not exist. Therefore, we can select the refracted wave that is eliminated by total reflection. 相似文献
10.
高掺镁铌酸钾晶体的主折射率及其温度系数的测量 总被引:1,自引:0,他引:1
本文报道掺5mol%MgO的铌酸锂(liNbO_3)晶体的主折射率n_o、n_o及其温度系数.用自准直法在0.5398μm、0.6328μm、1.0795μm和1.3414μm波长上,并在20℃~160℃温度范周内,测量了该晶体的主折射率,并获得在这些波长上的折射率温度系数.修正的Sellmeier方程的常数也在20℃~160℃温度内推算出.用此结果计算室温的二次谐波I类临界相位匹配角与实验值符合得很好,又计算二次谐波的非临界相位匹配温度,其结果也与实验值较符合. 相似文献
11.
Mechanical behaviour of wood considered as an orthotropic solid can be determined with ultrasonic technique. The propagation phenomena in wood are complex and theoretically are regulated by Christoffel's equation. Three type of waves can propagate in wood. During the propagation phenomena three slowness sheets are observed, corresponding to a fast longitudinal wave (inner sheet) and two shear waves, one fast and one slow (outer sheet). These waves are submitted continuously to mode conversion phenomena. The polarization angle changes when the propagation direction is out of the principal directions of symmetry of the material. In this article an analysis of the propagation phenomena in tridimensional representation is performed for different wood species. This approach contributes to the understanding of dynamic aspects of particle displacement associated with the wave fronts propagation. Globally, the anisotropy of each species, expressed by their acoustical behaviour is well represented. 相似文献
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ZHANG Shujun- CHENG Zhenxiang- LI Guangming- WANG Changqing- HOU Xueyuan- SUN Yuming- Y. T. Chow- SHAO Zongshu- CHEN Huanchu- 《Chinese Journal of Lasers》2000,9(3):282-286
1 Introduction Inthepastfewyears,smallsizedSFDlaserhasattractedgreatattentions.Laserdiode(LD)pumpedsolidstatelasershavebeenfoundveryusefulinthefieldsofmilitary,industry,medicaltreatmentandscientificresearchesduetotheadvantagesofhighstability,compactness… 相似文献
13.
We theoretically studied a left-hand structure based on a two-dimensional (2D) photonic crystal (PC)with a negative refractive index. The propagation of electromagnetic waves in the proposed PC structure is investigated through dispersion characteristic analysis and numerical simulation of field pattern. The designed PC structure can exhibit all angle negative refraction, and the corresponding effective refractive indices along all directions are almost same and close to the ideal value of -1. A flat lens formed from such a PC has been designed and its imaging properties have been investigated systematically. 相似文献
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ZHANG Shujun CHENG Zhenxiang LI Guangming WANG Changqing HOU Xueyuan SUN Yuming Y. T. Chow SHAO Zongshu CHEN Huanchu 《中国光学快报(英文版)》2000,9(3)
NdxGd1-xCa4O(BO3)3 (NdGdCOB) is a new self-frequency-doubling (SFD) solid-solution crystal. The second-harmonic generation (SHG) phase-matching (PM) curves were calculated by using refractive indices. The deff of NdGdCOB crystal along different PM directions were calculated according to the sellmeier equation and dijk data in which the (θ=66.8°, φ=132.6°) PM direction has the highest deff. SFD experiments were carried out with Ti:sapphire CW laser and pulsed dye-laser. A green laser output power up to 225 mW at 530 nm was achieved from a 7×3×3 mm3 crystal sample pumped by 1560 mW CW Ti:sapphire laser. The lasing threshold of SFD was lower than 1.8 mW along the PM direction (66.8°,132.6°). The optical-optical conversion efficiency was 14.4%. The conversion efficiency was 7.7% when 10×3×3 mm3 sample was side-pumped by the pulsed dye-laser tuned to 595.4 nm with 17.5 mJ energy and the lasing threshold is 1.2 mJ. 相似文献
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激光束与其散射光束在晶体中发生非线性和频作用,在满足非共线相位匹配条件时,可观察到二次谐波环的现象。本文以拆射率主轴坐标xoz平面为例,推导出了双轴晶体中环参数的近似表达式。并用计算机得出了精确数值解,与实验观察到环的形状完全一致,提出了一种寻找最佳二次谐波产生方向的方法。 相似文献
18.
Analytical expressions for the loss coefficient and the perturbed propagation constant are presented for planar leaky structures which may have media of complex refractive indices. Numerical calculations are reported for the loss variation with parameters such as the buffer refractive index, buffer thickness and superstrate refractive index. 相似文献
19.
The dynamics of a wave packet formed by tunnel-coupled forward and backward waves in a waveguide structure consisting of media
with different signs of real parts of their refractive indices is investigated. Expressions for coupled-wave amplitude and
reflection and transmission coefficients that are corrected for absorption are derived in the linear approximation. The expressions
governing the wave-packet duration and propagation velocity of its envelope maximum are derived, taking into account the second-order
dispersion, cubic nonlinearity, and dispersion of the nonlinearity. The possibility of efficient control of the forward wave
velocity by applying an external magnetic field is demonstrated. 相似文献
20.
Isaac Freund 《Optics Communications》2011,284(16-17):3816-3845
Circularly polarized, intersecting Gauss-Laguerre beams are shown to give rise to a rich array of unusual polarization structures whose properties can be tuned by varying the angle between the beams. These structures include Möbius strips with arbitrarily large, odd numbers of half twists, twisted ribbons with arbitrarily large, even numbers of half twists, and coronets (crowns). Six topological/geometrical indices are used to characterize these structures. Analytical expressions are given for some indices; others, which still present a considerable theoretical challenge, are treated numerically and illustrated graphically. It is argued that the polarization structures described here are, or soon will be, amenable to experiment. 相似文献