Development of the super-high angular resolution principle for X-ray imaging: Experimental demonstrations

Experimental demonstrations of the Super-High Angular Resolution Principle ( SHARP) for coded aperture imaging are presented. SHARP has been theoretically proven to be an extension of the coded aperture imaging system by taking advantage of the significant diffraction-interference effects of pinholes on the mask, which operates beyond the diffraction limit of a single pinhole. We first set up an optical experiment, the so-called SHARP-O, in order to verify the theoretical predictions on SHARP. The images of point sources are successfully reconstructed, with an angular resolution of about 26 arcsec and position accuracy of 2 arcsec, whereas the diffraction limit of a single mask pinhole in the mask is 870 arcsec. We then set up a SHARP-X demonstration experiment at an X-ray beam line facility; encouraging results are obtained, indicating that the SHARP concept is feasible in the soft X-ray band. It is thus possible to achieve sub-arcsec X-ray imaging with a simple coded mask system working beyond the diffraction limit of a single pinhole.