  The correction of multiple aberrations in an optical system requires
different optical elements, which increases its cost and complexity.
Metasurfaces hold great promise to providing new functionality for miniaturized
and low-cost optical systems. A key advantage over their bulk counterparts is
the metasurface's ability to respond to the polarization of light, which adds a
new degree of freedom to the optical design. Here, we show that polarization
control enables a form-birefringent metalens to correct for both spherical and
off-axis aberrations using a single element only, which is not possible with
bulk optics. The metalens encodes two phase profiles onto the same surface,
thus allowing switching from high resolution to wide field of view operation.
Such ability to obtain both high resolution and wide field of view in a single
layer is an important step towards integration of miniaturized optical systems,
which may find many applications, e.g., in microscopy and endoscopy.
