A method and device for determining refractive index of an object compared to a refractive index of a surrounding medium. The object is exposed to a laser object beam and the scattered light interferes with a laser reference beam to obtain a hologram. The hologram is analyzed for phase information, and based thereon, it is determined if the refractive index of the object is higher or lower than the refractive index of the surrounding medium.

Method and apparatus for holographic refractometry

Verfahren und vorrichtung zum pruefen von flaechen

The arrangement for the interferometric measurement of objects has a light source for object illumination and for at least one reference beam. It contains at least one detector with an associated objective for detecting the light scattered by the object. The scattered light (14, 16) is superimposed on the reference beam (15). The optical arrangement (4-6) for superimposing the scattered light on the reference beam is arranged between the detector (9) and the objective (8). It contains a beam divider cube and spherical mirror. ADVANTAGE - Enables simple, flexible handling of variations of the scattered light.

Interferometric measurement arrangement for objects - contains optical system with beam divider cube and spherical mirror superimposing light scattered by object onto reference beam

Method for holographic refractometry

A holographic interferometric, or moire metric method of determining deformations or position variations of objects or refractive index variations in transparent bodies, fluids or gases uses at least two object images contg. frequency patterns for different object conditions sequentially imposed at a scanning plane. The method enables the images to be quickly and practically evaluated and to be made visible. The local intensity modulations of the hologram image or moire pattern of two distinct object conditions are imposed on a radiation sensitive storage screen, pref. a t.v. screen. The patterns are scanned electronically and the corresp. overlayed output signals converted in an evaluation unit using time modulation.

Schwomma, Otto, Dr., Schwechat

Papers

Measuring deformation or variations in position or refractive index - using holographic-interferometric or Moire patterns for rapid evaluation