At-wavelength metrology using the moiré fringe analysis method based on a two dimensional grating interferometer

A two-dimensional (2D) grating interferometer was used to perform at-wavelength metrology. A Fast Fourier Transform (FFT) of the interferograms recovers the differential X-ray beam phase in two orthogonal directions simultaneously. As an example, the X-ray wavefronts downstream from a Fresnel Zone plate were measured using the moiré fringe analysis method, which requires only a single image. The rotating shearing interferometer technique for moiré fringe analysis was extended from one dimension to two dimensions to carry out absolute wavefront metrology. In addition, the 2D moiré fringes were extrapolated using Gerchberg's method to reduce the boundary artifacts. The advantages and limitations of the phase-stepping method and the moiré fringe analysis method are also discussed.

► A rapid and sensitive strip test for CPPU (forchlorfenuron) detection is reported.
► Carbon nanoparticles were used for antibody labelling.
► A common flatbed scanner was employed to the quantitate strip spots.
► The new method was successfully applied to the analysis of the field samples.