Kerr effect of molecular oxygen at lambda=1064 nm: experiment and theory

We report a new measurement of the Kerr effect of molecular oxygen at lambda = 1064 nm. The experimental value reported for the anisotropy of the index of refraction Delta nlu, (3.15+/-0.85)x10-25 m2 V-2 atm-1, is in good agreement with the value of 3.4x10-25 m2 V-2 atm-1 obtained via an ab initio calculation. We show that the dependence of the effect on the pressure is not linear because of the presence of a collision induced absorption band around 1060 nm due to the transition from the X3Sigma-g ground state to the 1Deltag state. We also give the value of the quadratic anisotropy Deltanqu (-1.03 +/- 0.68) x 10-25 m2 V-2 atm-2. We finally compare our ab initio theoretical and experimental results with previous existing data.