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 th e character of the signals developed in these experiments. For example, ell ipticity introduced by stress-induced birefringence can easily influence su ch 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 magn etic circular birefringence. A general expression for the magnetic rotation spectroscopy signal is derived and compared to experimental results. An ex pression for the detection sensitivity is developed by taking shot noise an d rms laser power fluctuations to be the dominant noise sources. (C) 1999 O ptical Society of America.