Dispersion of the Kerr Electro-Optic Effect in the Short Infrared Spectrum

Abstract

Measurements of the Kerr electro-optic effect have been made on carbon disulphide, nitrobenzene, $o$-nitrotoluene, chlorobenzene, and halowax oil over a spectral region extending from the sodium lines to beyond 1.6μ (2.1μ for C${\mathrm{S}}_2$), or some three times the wave-length range previously investigated by other observers. A spectro-radiometric method was used, involving effectively the measurement of the minor axis of the ellipse into which the plane polarized radiation is converted by the electrostatic stress in the Kerr cell. The potentials across the cell of 3300 to 31,000 volts were furnished by a kenotron and condenser equipment. The Havelock formula for electro-optic dispersion $K=\frac{C{(n^2-1)}^2}{n\lambda }$ and two others have been tested in connection with the results. In most cases the agreement with the Havelock formula is somewhat better than with the others and for C${\mathrm{S}}_2$ this law fits the observed dispersion almost within the limits of experimental error throughout the spectral range investigated. Beyond 1μ the dispersion of all the liquids is much the same and the agreement with all these formulas reasonably good. In fact, for this region the Kerr effect is very nearly proportional to the inverse wave-length.