  The far-field resolution of optical imaging systems is restricted by the Abbe
diffraction limit, a direct result of the wave nature of light. One successful
technological approach to circumventing this limit is to reduce the effective
size of a point-spread-function. In the past decades, great endeavors have been
made to engineer an effective point-spread-function by exploiting different
mechanisms, including optical nonlinearities and structured light illumination.
However, these methods are hard to be applied to objects in a far distance.
Here, we propose a new way to achieve super-resolution in a far field by
utilizing angular magnification. We present the first proof-of-concept
demonstration of such an idea and demonstrate a new class of lenses with
angular magnification for far-field super-resolution imaging. Both theoretical
and experimental results demonstrate a more than two-fold enhancement beyond
the angular-resolution limit in the far-field imaging. The proposed approach
can be applied to super-resolution imaging of objects in far distance. It has
promising potential applications in super-resolution telescopes and remote
sensing.
