Weak value amplified optical activity measurements

We present a new form of optical activity measurement based on a modified weak value amplification scheme. It has recently been shown experimentally that the left- and right-circular polarization components refract with slightly different angles of refraction at a chiral interface causing a linearly polarized light beam to split into two. By introducing a polarization modulation that does not give rise to a change in the optical rotation it is possible to differentiate between the two circular polarization components even after post-selection with a linear polarizer. We show that such a modified weak value amplification measurement permits the sign of the splitting and thus the handedness of the optically active medium to be determined. Angular beam separations of Delta theta similar to 1 nanoradian, which corresponds to a circular birefringence of Delta n similar to 1 x 10(-9), could be measured with a relative error of less than 1%. (C) 2011 Optical Society of America