NOVEL ELECTRO-OPTICAL LIGHT MODULATORS.
ILLINOIS UNIV URBANA DIGITAL COMPUTER LAB
Pagination or Media Count:
To the well developed family of Kerr-cell type devices two novel electro-optical devices are proposed a direct intensity modulator and a light beam deflecting device. The theoretical background of the electro-optically induced birefringence is examined. Starting from the anisotropic material equations and Maxwells differential equations, an analytical derivation of this birefringence is given. Furthermore it is shown how the electrooptical effect influences the material equations, hence its effect on the birefringence is derived. The experimentally determined electro-optic effect is tabulated for the most important materials. The new intensity modulator operates on the principle of electro-optically controlled partial reflections. A systematic and quantitative procedure is presented for the optimized design of a broadband intensity modulator. The modulating frequency of the device is fundamentally limited only by the dispersion of material parameters. The beam deflecting device uses the fact that a variation of the index of refraction n causes a light beam to change direction of propagation. The desired variation of n hence the deflection of the beam can be achieved by placing an electro-optical material in a suitable electric field distribution. The experimental results obtained with three divices support the theoretical predictions. Intensity modulation up to 50 and a deflection of .003 radian were observed in the laboratory using nitrobenzene as the electro-optic material.