COTTON-MOUTON EFFECT OF MOLECULAR-OXYGEN - A NOVEL MEASUREMENT

A novel apparatus to measure small magnetic birefringences is describe d. It is based on a high-finesse Fabry-Perot cavity, to which a Nd:YAG laser is frequency locked, and on a 1.1-T permanent dipole magnet. We report the new measurement of the magnetic anisotropy of the refracti on index (Cotton-Mouton effect) for molecular oxygen at lambda = 1064 nm, T = 20 degrees C. Our result, Delta n(O-2) = (-2.29 +/- 0.08)10(-1 2)(B/1 T)(2)(P/1 atm), is consistent with the existing theoretical pre dictions and falls in line with the previous experimental results take n at different wavelengths. (C) 1998 Optical Society of America.