Characterization of a one dimensional focusing compound refractive lens using the rotating shearing interferometer technique

A one dimensional (1D) compound refractive lens (CRL) has been characterized using the grating based rotating shearing interferometer technique. The method is based on the calculation of moiré fringes orientation to sense wavefront information. The phase shift and the optical aberration introduced by the 1D CRL on an X-ray beam were retrieved from a single moiré fringe image. The radius of curvature of the lens at the apex was derived. This physical radius of the CRL, which is also closely related to the focal length of the 1D CRL, was shown to vary with the incident angle of the incoming X-ray beam onto the CRL. The experimental measurement agreed very well with the theoretical expectations.