共查询到20条相似文献,搜索用时 31 毫秒
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Yasuo Minami 《Applied physics. B, Lasers and optics》2014,117(3):969-972
Thermally excited capillary waves propagate everywhere on a liquid surface. The relationship between the frequency and wavelength of the capillary wave reflects the surface tension of the liquid, and the lifetime of the capillary wave reflects the shear viscosity of the liquid. By observing a capillary wave with inelastic light-scattering spectroscopy, we can obtain the surface tension and the viscosity from the frequency modulation of the light and the spectral width of the scattered light. In this study, we observed capillary waves on liquid metal using high-resolution spectroscopy, and successfully measured their properties in a non-contact manner. In the experiment, values were obtained at a frequency of about 20 kHz. The values were equivalent to those at 0 Hz, since the properties of liquid metals are constant at least in the frequency region from 0 to several tens of kilohertz. 相似文献
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通过采用将入射光掠入射到频率为几百赫兹的衰减低频液体表面波上,观察到了清晰的间距分布具有明显非对称性的衍射条纹。当入射光掠入射到低频液体表面上时,衍射图样非对称分布具有普遍性。理论上得到了考虑表面波衰减影响后观察屏处衍射光强分布的解析表达式。理论结果表明:衍射图样的这种非对称分布与衍射级次、入射光波波长、液体表面波波长及表面波衰减系数有关;正负级次衍射亮条纹距离中央零级亮条纹的间距体现表面波衰减信息;正衍射级次之间以及负衍射级次之间的条纹间距体现表面波波长信息。利用所提出的方法实现了对几百赫兹液体表面波的衰减系数的实时便捷测量。 相似文献
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A. A. Karetnikov N. A. Karetnikov A. P. Kovshik E. I. Ryumtsev E. V. Aksenova E. V. Kryukov V. P. Romanov 《Optics and Spectroscopy》2010,108(6):947-953
The effect of an alternating electric field on the trajectory of an extraordinary light wave in a layer of a chiral liquid
crystal with a 180° turn of the director is studied. In this structure, in the absence of the field and at a large angle of
incidence of the light wave on the liquid crystal layer, the light undergoes refraction inside the layer. It is shown that
the deformation of the director that arises under the action of the electric field changes the character of refraction of
the extraordinary wave and the layer begins to transmit the light. The threshold voltage of this effect is determined. The
dynamics of the effect is studied. At large voltages, in addition to the extraordinary wave, an ordinary light wave is observed
in the light passed through the cell. The ordinary wave intensity is modulated by the initial frequency of the control signal,
whereas the extraordinary wave intensity is modulated by the double initial frequency. 相似文献
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The pulsation of ultrasonic cavitation bubbles at various dissolved-air concentration in a sonochemical reaction field of standing-wave type is investigated experimentally by laser-light scattering. When a thin light sheet, finer than half the wavelength of sound, is introduced into the cavitation bubbles at an antinode of sound pressure, the scattered light intensity oscillates. The peak-to-trough light intensity is correlated with the number of bubbles that contribute to the sonochemical reaction. It is shown that as the dissolved air concentration becomes higher, the weighted center of the spatial distribution of the peak-to-trough intensity tends to shift towards the liquid surface. At higher concentration of the dissolved air, a great deal of bubbles with size distribution generated due to coalescence between bubbles disturbs sound propagation to change the sound phase easily. A standing wave to trap tiny oscillating bubbles is established only at the side which is nearer to the liquid surface. Also at higher concentration, liquid flow induced by drag motion of bubbles by the action of radiation force becomes apparent and position-unstable region of bubble is enlarged from the side of sound source towards the liquid surface. Therefore, the position of oscillating bubbles active for sonochemical reaction is limited at the side which is nearer to the liquid surface at higher concentration of the dissolved air. 相似文献
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Yaping Zhang Junchang Li Wenming Yang Jianqiang Zhang Peng Wang Wei Xu 《Optical and Quantum Electronics》2013,45(10):1077-1086
The objective surface is considered as the scattering plane; frequency spectrum of a digital hologram transmission light is studied when the reference light and reconstruction wave are spherical waves. The relation between relevant parameters and the object light, conjugate object light and zero-order diffraction wave frequency spectrum distribution. The research results show that: each frequency spectrum of the diffracted wave broadens to various degrees as the radius of the reconstruction wavefront decreases, and frequency aliasing is generated under certain conditions. Based on the research results, a new method that carries out high-pass filtering processing without zero-order diffraction interference upon digital hologram is proposed and the reconstruction experimental proof for eliminating the interferential changeable magnification wave is given. 相似文献
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The scanning of a one-dimensional light intensity distribution was accomplished by employing the acousto-optic interaction of surface waves on LiNbO3. The acoustic signal was 200 nano-seconds long with a center frequency of 100 MHz. To produce a large interaction length, the light propagates through the crystal parallel to the surface on which the acoustic surface wave is launched. The detected diffraction signal yields a temporal representation of the spatial intensity distribution. 相似文献
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An analytic intensity expression of the reflected light from a liquid surface with acoustic wave at a few tens Hertz was derived. The expression displays a distinct modulated oscillation. Meanwhile high visibility and modulated interference fringes were obtained experimentally. Line scans across the reflection patterns indicate that the theory predication is well consistent with the experimental data. Moreover, a practical technique can be developed, based on this study, to determine the wavelength and amplitude of the SAW at these frequencies as well as the dynamic surface tension. 相似文献
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M. R. Hakobyan R. B. Alaverdyan R. S. Hakobyan Yu. S. Chilingaryan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2014,49(4):144-150
Theoretical and experimental results on thermocapillary hydrodynamic surface waves induced in liquids by travelling spatially periodical distribution of light intensity are reported. The phase of local elevation in capillary waves is close to the phase of interference pattern when frequency is far from zero and from eigen frequency of free capillary waves. This phase difference is exactly π/2 for zero frequency. 相似文献
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产生多个高光强梯度局域空心光束的理论与实验 总被引:1,自引:1,他引:0
在实验中用贝塞尔光束与球面波叠加得到多个具有高强度梯度的局域空心光束(BB)。用衍射理论分析了贝塞尔光束与球面波叠加的光场,借助软件对两光场相干叠加的光强分布进行了模拟,结果表明在球面波的焦点附近能够形成多个高强度梯度的BB。实验中贝塞尔光束和球面波分别用轴棱锥和透镜对平行光聚焦获得,使两光场在同一传播轴上相干叠加,在球面波焦点附近观察到多个BB。通过对比可知,贝塞尔光束与球面波叠加所得BB比用两束贝塞尔光束干涉产生的BB在暗域处具有更大的光强梯度,更有利于稳定的粒子囚禁。 相似文献
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根据表面波声光效应的原理,实验上建立了固体表面微振动的激光衍射测量系统.当激光斜入射到微振动引起的液体表面波上,观察到了清晰、反衬度非常高的衍射图样.利用MATLAB软件对拍摄的衍射图样进行扫描,得到了衍射光斑的光强分布图,并根据衍射图样宽度与表面波振幅的解析关系式,求出了液体表面波的振幅,其大小在微米量级.改变样品池中液体的深度,测得不同深度下液体表面波的振幅,给出了表面波振幅与液体深度之间的解析关系,并发现了液体对微振动的放大效应.利用液体对微振动的放大效应,求出了固体表面微振动的振幅,实现了固体表面微振动的探测. 相似文献
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根据表面波声光效应的原理,实验上建立了固体表面微振动的激光衍射测量系统.当激光斜入射到微振动引起的液体表面波上,观察到了清晰、反衬度非常高的衍射图样.利用MATLAB软件对拍摄的衍射图样进行扫描,得到了衍射光斑的光强分布图,并根据衍射图样宽度与表面波振幅的解析关系式,求出了液体表面波的振幅,其大小在微米量级.改变样品池中液体的深度,测得不同深度下液体表面波的振幅,给出了表面波振幅与液体深度之间的解析关系,并发现了液体对微振动的放大效应.利用液体对微振动的放大效应,求出了固体表面微振动的振幅,实现了固体表面微振动的探测. 相似文献