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1.
A theory is developed to describe sequential quasi-synchronous wave interactions in an active non-linear medium with a regular domain structure inside a cavity. In particular, sequential processes of quasi-synchronous third-harmonic generation and quasi-synchronous parametric amplification that occur in a Nd:Mg:LiNbO3 crystal with a regular domain structure under low-frequency pumping are analyzed. The efficiency of these nonlinear optical processes is studied as a function of both the reflection coefficient of the exit mirror and the linear loss in the medium. 相似文献
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A. L. Gurskii I. I. Zholnerevich V. I. Kozlovskii I. I. Kulak E. V. Lutsenko A. I. Mit'kovets G. P. Yablonskii 《Journal of Applied Spectroscopy》1999,66(5):794-801
We present results of investigations of the directionality diagram and mode structure of radiation of semiconductor lasers
with electron pumping that have microrelief reflectors instead of a blind mirror and output mirrors, whose coefficient of
reflection depends on the wavelength and the angle of light propagation. Application of such mirrors allows one to narrow
the spectrum of output radiation of the lasers, simultaneously reducing the threshold and increasing the output power. The
discovered multilobe structure of the directionality diagrams is explained on the basis of geometrical optics. The possibility
of controlling the directionality of radiation depending on the spectral and angular characteristics of the output mirror
is shown.
Reported at the Second International Scientific and Technical Conference on Quantum Electronics, Minsk, November 23–25, 1998.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 5, pp. 092–697, Septemter–October, 1999. 相似文献
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The law of reflection of light by a moving mirror in the case of special Lorentz transformation is well known. We have derived
the law of reflection of light by a moving mirror in the case of the most general Lorentz transformation. It has been observed
that in the case of special Lorentz transformation, the law of reflection of light by a moving mirror is very simple but in
the case of the most general Lorentz transformation, the law of reflection of light by a moving mirror is very complex.
相似文献
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E.G. McRae 《Surface science》1975,47(1):167-180
The amplitude coefficients of electron reflection at crystal surfaces are complex numbers, each of which may be characterized by a reflection intensity (the squared modulus of the coefficient) and a phase. The phase of reflection of very low energy (? 10 eV) electron reflection is described on the basis of existing theory, and experimental approaches to phase determination are reviewed. Theoretical properties of the phase are described on the basis of the two-beam dynamical theory of diffraction. The model considered is an idealized substrate crystal with an attached selvedge (surface region). The indirect effect of inelastic scattering (absorption) is included by going to complex values of the electron energy or of the surface-normal component K of the propagation vector. In the absence of a selvedge the phase is determined solely by the band structure of the substrate crystal. If a selvedge is present there are large additional effects on the phase associated with zeros of the amplitude coefficient of reflection on the complex K plane. The experimental approaches considered are: (1) measurement of the kinetic energy distributions of ions produced in the field ion microscope, and (2) measurement of the periodic deviations from the Schottky line in field-assisted thermionic emission and photo-emission. Recent results of phase determination for W (011) surface by method (1) are summarized and compared with theoretical expectations. 相似文献
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A dynamic phase-conjugate mirror based on CdF<Subscript>2</Subscript> crystals with bistable centers
A. E. Angervaks S. A. Dimakov S. I. Kliment’ev A. I. Ryskin A. S. Shcheulin 《Optics and Spectroscopy》2005,98(6):934-937
A four-wave phase-conjugate mirror on reflection gratings recorded in a CdF2 crystal with bistable centers has been studied experimentally. The mirror reflectivity and speed have been measured, and the coefficient of third-order nonlinearity of this medium has been estimated. The quality of the wave reflected from the phase-conjugate mirror has been investigated in model experiments. 相似文献
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The dependence of the nonlinear reflection coefficient R of a mirror with a wavefront reversing surface on the intensity I
of the reference wave is analyzed in terms of a phenomenological model of a medium having a nonlinear Fresnel reflection amplitude
coefficient φ. Substantial differences are revealed for media having different signs of the nonlinearity coefficient β=(dφ/dI).
It is shown that R is related to the magnitude D of the dynamic range of the wavefront reversing mirror by the expression
RD=Qs' where Qs is a parameter which defines the “quality” of the nonlinear medium.
Far-Eastern State Academy of Communications. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 68–70,
August, 1997. 相似文献
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Tunable, grating-assisted ring resonator based optical mirrors are analyzed and their characteristics numerically evaluated. Mode number selection rules are presented to aid mirror optimization for high, narrow-band reflection and efficient sidelobe suppression. Data is presented on tuning sensitivity, on the effect of coupling on bandwidth and reflection coefficient, and on the influence of waveguide and grating loss on mirror performance. Group delay in the presence of loss and circuit parameter variations is also treated. 相似文献
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The coefficient of X-ray reflection from a bent Bragg mirror is obtained on the basis of the principle of locality. The focusing
of X-ray quanta by bent crystals is considered. The caustics for the X-rays reflected from the bent Bragg mirror are determined. 相似文献
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Frequency and reflection angle of probe radiation from a refractive-index inhomogeneity induced by an intense pumping pulse in quartz glass and moving with a relativistic velocity are calculated. Conditions under which the normal component of the wave vector of the reflected wave is directed to the opposite or to the same direction as the same component for the incident wave are determined. Comparison with the case of radiation reflection from a relativistic mirror in vacuum is performed. Conditions of the appearance of the Vavilov-Cherenkov radiation from a relativistic refractive-index inhomogeneity induced in the medium by an intense laser pulse are discussed. 相似文献
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ZnO薄膜光学常数测量 总被引:7,自引:0,他引:7
利用Kramers-Kronig方法(K-K方法)测量了ZnO薄膜的复介电常数和复折射率(折射率和消光系数)。为了满足K-K方法所要求的条件,光源发出的光束通过一个特殊设计的中间带孔的反射镜垂直投射到ZnO薄膜表面,在ZnO薄膜表面产生的反射光穿过反射镜中间的小孔进入单色仪,从而测量出正入射情况下ZnO薄膜的反射光谱。对有限波段下测量的数据经合理的外推后,得出全波段的薄膜反射谱,然后利用K-K方法计算出ZnO薄膜的复介电常数和复折射率。实验结果表明,氧化锌薄膜在可见光范围内的折射率近似为一常数3.5;在430nm附近出现折射率最大值,而在短波长范围所对应的折射率大大降低,其值在0.5—2.5之间起伏波动。 相似文献
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针对随机起伏冰面的声散射计算问题,利用修正反射系数的Kirchhoff近似方法计算了高斯起伏冰面的三维声散射。在计算模型中引入了冰面局部统计平均反射系数的概念,将二维高斯起伏冰面的散射分为相干散射和非相干散射,分别得到两类散射成分的散射系数公式,计算了高斯起伏冰面三维声散射的散射强度。分析了散射强度与随机起伏冰面的均方根高度、声波入射角度及频率的关系。通过实验室水池中高斯起伏冰面的散射强度测量实验,对理论模型的计算结果进行了验证。将实验结果分别与采用冰面局部统计平均反射系数的模型计算结果和文献中采用平整冰面镜反射系数的模型计算结果进行了对比,采用冰面局部统计平均反射系数的模型计算结果与实验测量值吻合较好。 相似文献
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P. E. Dyer 《Optical and Quantum Electronics》1982,14(4):327-330
The influence of interference due to weak reflections from anti-reflection coated surfaces in CO2 laser optics is discussed and analysed. In certain cases quite low reflection levels (1%) are shown to lead to uncertainties in the mirror transmission coefficient or produce a non-uniform power loading on the mirror surface, resulting in damage. 相似文献
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研究了多光束非定域干涉现象,得到了多光束非定域干涉的透射光强分布函数。理论研究结果表明,干涉圆环中心位置光强与定域干涉结果一致。对得到的多光束非定域干涉透射光强分布函数进行了数值分析,分析结果表明随着镜面反射系数的增加,非定域干涉条纹变得更加锐细,光谱分辨率提高,同时在低干涉级次处出现了噪声,并且反射系数越高,噪声越明显。在镜面间距不变的情况下,通过改变观察屏位置,对透射光强分布进行数值分析,结果表明干涉级次与干涉圆环倾角的余弦值存在线性关系,通过求斜率可以得到镜面间距。保持观察屏位置不变,通过改变镜面间距,数值分析结果表明干涉级次与干涉圆环半径平方存在线性关系,并且直线斜率与镜面间距也存在线性关系。 相似文献
18.
B. B. Sevruk 《Journal of Applied Spectroscopy》2001,68(1):101-109
A procedure of numerical modeling of an optical parametric oscillator in the cavity–dumping mode has been developed. For the optical parametric oscillator based on a KTP crystal the dependences of the temporary profile and energy of the signal pulses (s = 1.57 m) on the time of switching and depth of modulation of the reflection factor of the output mirror at prescribed length and energy of the Gaussian pulse of pumping an Nd:YAG laser (p = 1.064 m) are calculated. An optimum mode of controlling extraction of radiation that ensures the maximum efficiency of conversion due to reduction of nonlinear losses has been found. The possibility of forming gigantic pulses by the optical parametric oscillator with the peak intensity greatly exceeding the intensity of pumping is shown. 相似文献
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The linearized problem of reflection of a plasma wave from the boundary of a degenerate collisional plasma occupying the half-space is stated and analytically solved for the first time. As the boundary conditions, both mirror and diffuse reflections of electrons are applied. The reflection coefficient is found as a function of the input parameters. The long-wave limit is analyzed. 相似文献
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It is demonstrated that a reflection interferometer with optical properties of a three-mirror system in transmitted light can be created by including a phase grating in the structure of an input mirror. The response function is determined, a technique for the selection of parameters for the formation of spectral characteristics of the reflection coefficient is considered, and results of calculations are presented. 相似文献