干涉亮条纹强度的不均匀分布

建立了低频液体表面声波的激光干涉测量系统,实验上不仅得到了清晰、稳定的干涉条纹,而且首次发现干涉条纹的强度分布具有空间不均匀性,干涉条纹被限定在一定的空间区域内,中心干涉条纹强度最小,向两边强度逐渐增大,在两边界位置达到极大.根据波动光学原理,得到了干涉条纹分布的解析表达式,并给出了低频表面波振幅、波长与干涉条纹空间限度、干涉条纹间距的数学表达式.理论规律与实验结果吻合较好.

The Nonuniform Distribution of Bright Fringe Intensity in Interference Patterns

A kind of laser interference technique was designed to measure low-frequency liquid surface wave(LFLSW).Steady and high visible interference patterns are obtained,and the spatially nonuniform distribution of interference intensity is observed in the experiment for the first time.The interference fringes are confined in a certain space range.The intensity of the center fringe is the smallest and the intensity increases gradually towards the two sides.At the both extreme positions of this range,the intensity gets the biggest.An analytic intensity distribution expression is derived theoretically according to principles of wave optics.At the same time,the mathematical expression of LFLSW amplitude and the wavelength with the angle space of the interference fringes and the angle width of the interference fringe range is given.The results show that the theory predication is basically consistent with experimental data.