Multifunctional focusing and accelerating of light with a simple flat lens

The wavefronts emerging from phase gradient metasurfaces are typically sensitive to incident beam properties such as angle, wavelength, or polarization. While this sensitivity can result in undesired wavefront aberrations, it can also be exploited to construct multifunctional devices which dynamically vary their behavior in response to tuning a specified degree of freedom. Here, we show how incident beam tilt in a one dimensional metalens naturally offers a means for changing functionality between diffraction limited focusing and the generation of non-paraxial accelerating light beams. This attractively offers enhanced control over accelerating beam characteristics in a simple and compact form factor.