Tomsk State University. Physical Department.
Laboratory of training physics experiment
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Circular  Double  Refraction       

Fresnel explained the phenomenon optical rotation as light propagates at different speeds with R and L circular birefringence. For the experimental verification he made a composite prism consisted of three quartz prisms. The central prism was made of left-handed quartz, while the two edged of right-handed quartz.

We have managed to carry out the experiment with a similar composite quartz prism. The main complexity is that the light propagate against circular birefringence is very little, because the relative refraction index is only ?n=0.00007. That is why we used a telescopic tube with 20-fold angular magnification in order to increase the space between two images, and amounted the setup with large distances between the elements.

Using the telescopic tube there was a real image of the slit on the screen which was being illuminated by nonpolarized laser beam (photo 1). The distance between the tube and the slit was about 4 m; the distance from the tube to the screen was about 7 m. The composite prism had been arranged directly in front of the tube that enabled to double the slit image up to 2 cm (photo 2). Since the polarization of these two images is circular, the polarizer being behind the tube equally weakens the brightness (photo 3). The analysis with quarter-wavelength plate allows of suppression by turn the right and left slit images (photo 4).
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