Diffraction-limited superresolution ptychography in the Rayleigh-Sommerfeld regime.

Superresolution in lensless near-field ptychography is demonstrated via the application of a strongly curved illumination function. The reconstruction is performed using the Rayleigh-Sommerfeld diffraction integral, which is implemented via a pixel-size adjustable angular spectrum method. In this manner, the reconstructed object details, which are not only smaller than the pixel size of the sensor but even smaller than the smallest resolvable object detail defined by the effective NA of the 2D sensor, are enabled.

Pixel size adjustment in coherent diffractive imaging within the Rayleigh-Sommerfeld regime.

The reconstruction of the smallest resolvable object detail in digital holography and coherent diffractive imaging when the detector is mounted close to the object of interest is restricted by the sensor's pixel size. Very high resolution information is intrinsically encoded in the data because the effective numerical aperture (NA) of the detector (its solid angular size as subtended at the object plane) is very high. The correct physical propagation model to use in the reconstruction process for this setup should be based on the Rayleigh-Sommerfeld diffraction integral, which is commonly implemented via a convolution operation.