Multifunctional light sword metasurface lens

The depth of focus of an imaging system determines the range of change for both the position of focal plane and image plane. Although a typical light sword optical element with angular modulation of phase transmittance can extend its focus of depth due to its angular variation of the optical power, it lacks rotational symmetry and exhibits a junction, rendering its fabrication extremely difficult. Optical metasurfaces provide an unusual approach to develop such a device due to their unprecedented capability in the manipulation of light propagation in a desirable manner. We propose and experimentally demonstrate a light sword metasurface lens with multiple functionalities. The position of focal segments can be controlled by changing the polarization state of the incident light. The developed ultrathin, ultraflat device can facilitate device miniaturization and system integration and may find applications in various fields such as optical coupling, imaging, and interconnections.