Microscopic imaging of circular dichroism using a polarizing undulator

A new type of scanning microscope for observing circular dichroism (CD) images of samples was developed. As an illuminating light source, a polarizing undulator which generates right- and left-handed circularly polarized synchrotron radiations (SR) alternately, was used in the microscope. The SR from the polarizing undulator was focused to form a microbeam with a spot size of less than 1 mu m, by axially symmetric mirrors. The sense of rotation of circular polarization of the undulator radiation was modulated with a frequency of about 2 Hz. Two-dimensional CD images of a thin film of d-10-camphorsulfonic acid, which is one of the standard samples used for measuring a CD spectrum, were obtained by this microscope.