低频液体表面波衍射条纹的不对称性

实验上实现了低频液体表面波的光衍射,当表面波波长远大于入射光波波长时,得到了稳定、清晰的衍射图样,并首次发现了衍射条纹具有明显的不对称分布.理论上对表面波衍射的近似条件进行了分析,得出了各级衍射条纹角宽度的解析表达式,解释了衍射条纹的非对称分布.衍射图样的不对称分布具有普遍规律,可观察的明显程度与表面波的波长和光波波长的比值有关,在能观察到衍射效应的条件下,当表面波波长远大于光波波长,非对称分布越明显,当表面波波长远接近光波波长时,衍射条纹可近似的看成是对称分布的.

The Asymmetry of Diffraction Patterns from Liquid Surface Waves

Light diffraction from liquid surface acoustic waves at low-frequency was experimentally realized.In the experiment steady and visible diffraction patterns were obtained,and the obvious asymmetry of patterns was observed for the first time.Theoretically the approximate conditions of the surface wave diffraction were analyzed,and the corresponding analytic expression of angle width of diffraction patterns was derived,which explained the asymmetry distribution well.The symmetry distribution of diffraction pattern is a universal rule.And whether it can be observed obviously depends on the ratio of the wavelength of surface wave and light.The bigger the ratio is ,the more obvious the asymmetry distribution is .Under the condition that the surface wavelength is close to the light wavelength,the diffraction patterns can be considered as a kind of symmetry distribution approximately.