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| Call for Papers>>Final Program |
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| Abstract of admission as follows: |
| Instrument for Measurement of Thickness, Index of Refraction and Diffraction Efficiency of Holographic Films |
| J. Eichler, S. Chruscicki, C. Schneeweiß, G. Ackermann
Beuth Hochschule für Technik, University of Applied Science
Seestr. 64, 13347 Berlin, Germany |
| Abstract |
| Index of refraction and film thickness are important parameters for holographic films of different types, i.e. silver halide material or dichromate gelatine. A simple aparatus is described to measure these parameters based on white light interference (H. I. Bjelkhagen, Silver-Halide Recording Materials for Holography and Their Processing, Springer 1999). A nearly parallel white light beam is created by positioning a small light source in the focus of a lens. The beam is directed on the surface of the holographic film. Using a lens, the reflected beam is collimated on the intrance slit of a small computer coupled spectrometer. The experiment is performed at two different angles of reflection. The spectra are analyzed and interference effects are observed resulting in maxima and minima in the spectra with distances of several nm. From the wavelengths of the extrema the index of refraction and film thickness are calculated. The results for the index of refraction can be compared with measurements using a commercial total reflection refractometer. The installation can also be used to measure the spectral diffraction efficiency of reflection holograms measuring the transmission spectra for a white light beam. Applications of the system are demonstrated investigating commercial and self-made dichromate gelatine films. As an example the index of refraction is measured depending on the exposure with a laser beam for different holographic processing methods. |
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