1 July 1990 High-precision refractometry of liquid samples using holographic interferometry
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Proceedings Volume 1319, Optics in Complex Systems; (1990) https://doi.org/10.1117/12.22227
Event: 15th International Optics in Complex Systems, 1990, Garmisch, Germany
A holographic interferometry technique for the measurement of the refractive index of transparent liquid samples is presented. 1 . MEASURENT PROCEDURE. The liquid under study is within a tank with an optical glass wedge. The refractive index is determined by comparison withthat of the glass wedge. The immersion tank is illuminatcd with a collimated beam of light. A diffuser plate is used after the tank to avoid the noise produced by the out of focus images of the light source and the optical components before the tank (Fig. 1). After a hologram of the wavefront transmitted through the sample has been recorded the glass wedge is removed and equally spaced straight fringes (Fizeau fringes) are observed. The separation between these fringes depends on the welge angle and the refractive index difference between the sample and the immersion fluid. It is important to have a sample with a wedge angle value adequate to the index matching to obtain observable fringes. It can he shown (Ref. 1) that the refractive index of the liquid can be determined using: N x tan a where N'' is the refractive fringes associated with the this technique depends on determined. index of the glass wedge used as reference n the number of spacement AX and is the wedge angle. The accuracy of the accuracy with which the spacing between fringes is Fig. 1. Hologram interferometer diagram. In
© (1990) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Diana Tentori, Diana Tentori, "High-precision refractometry of liquid samples using holographic interferometry", Proc. SPIE 1319, Optics in Complex Systems, (1 July 1990); doi: 10.1117/12.22227; https://doi.org/10.1117/12.22227

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