Analysis of imperfect polarizer effects in magnetic rotation spectroscopy.

Small amounts of ellipticity in the nominally linearly polarized light used in magnetic rotation spectroscopy play an important role in determining the character of the signals developed in these experiments. For example, ellipticity introduced by stress-induced birefringence can easily influence such signals more than does a nonzero polarizer extinction ratio. In addition, for nearly-crossed polarizers, an initial ellipticity allows one to probe magnetic circular dichroism instead of the more commonly investigated magnetic circular birefringence. A general expression for the magnetic rotation spectroscopy signal is derived and compared to experimental results. An expression for the detection sensitivity is developed by taking shot noise and rms laser power uctuations to be the dominant noise sources.