  We present the experimental reconstruction of sub-wavelength features from
the far-field intensity of sparse optical objects: sparsity-based
sub-wavelength imaging combined with phase-retrieval. As examples, we
demonstrate the recovery of random and ordered arrangements of 100 nm features
with the resolution of 30 nm, with an illuminating wavelength of 532 nm. Our
algorithmic technique relies on minimizing the number of degrees of freedom; it
works in real-time, requires no scanning, and can be implemented in all
existing microscopes - optical and non-optical.
