采用波面纵向平移全息干涉测量液体折射率

Measurement of the Refractive Index of Liquid Using Wavefront Lo ngitudinal Displacement Holographic Interferometry

本文提出一种测量液体折射率的新方法。利用掺铈铌酸锶钡 (SBN:Ce)在低功率 He- Ne激光下良好的全息记录性能实现全息干涉 ,在物光光路中插入一个装满待测液体的矩形槽 ,使再现物光波和直透物光波之间产生一个纵向平移 ,两列物光波在接收平面迭加干涉形成同心圆环形干涉条纹。通过测量圆环干涉条纹之间的间距求得待测液体的折射率。采用光折变晶体作为全息干涉的记录介质 ,不再需要任何化学或物理处理过程 ,避免了传统全息干涉测量中由于全息图复位不准造成的误差 ,并可多次重复使用 ,从而提高了系统的灵活性和测量精度。文中对该方法的系统结构、测量原理进行了分析 ,给出了测量结果。该方法的原理、结构简单 ,操作简便 ,并且具有较高精度。

A new method for measuring the refra ct ive index of liquid is proposed in this paper.It is based on the real-time holo graphic interferometry.A photorefractive crystal (PRC) is used as the recording medium in the holographic interferometer and a longitudinal displacement betwee n the reconstructed object wavefront and the present object wavefront is produce d by inserting a rectangular cell filled with a liquid sample under test into th e object light beam.The interference fringe pattern formed by these two object w avefronts is used as the measure of the refractive index of the liquid sample.Be casuse of using a PRC as the recording medium all the measurements are in situ,i .e.no chemical or physical processing is needed.The system configuration and the principle of the present method are analyzed,and some experimental results are given.The experimental results show that this method is simple,rapid and of suff icient precision.