The Electro-Optical Kerr Effect in Gases

The electric double refraction or Kerr electro-optical effect in C${\mathrm{O}}_2$ has been investigated as a function of the density and of the temperature. A method of study has been developed by means of which it is possible to work at several hundred atmospheres pressure and with high electric field strengths. The polarizing prisms and the Kerr cell are enclosed in the same pressure chamber thus eliminating errors due to strains in the windows. The double refraction of the emergent light is measured by means of a photoelectric cell arrangement. The Kerr constant $B$ in C${\mathrm{O}}_2$ was found to vary with density over the range 0.08 to 0.18 gm/${\mathrm{cm}}^2$ by about the amount to be expected from theory. The temperature variation, also, was in approximate accord with theory. Preliminary results show an easily measurable effect in oxygen and nitrogen, the former being larger.