Multi-focusing metalenses based on quadrangular frustum pyramid-shaped nanoantennas

This paper presents ultrathin multi-focusing metalenses that can produce several independent focusing spots, useful in imaging for light flow redistribution, even asymmetrical into many focal spots. The proposed design includes quadrangular frustum pyramids serving as individually tuned nanoantennas; their structure can be modified, facilitating wave-phase retardation tuning. Combining the propagation phase control with the Pancharatnam–Berry phase principle allows the screening of various cell structures. The specific design of the unit-cell structures makes the metalenses capable of single- and double-focusing at the required focal length. Thus, this metalens design might help in developing precision optics for micro-object manipulation. The data that support the findings of this study are available from the corresponding author upon reasonable request. •Quadrangular prism nano-antennas are used to design metalenses.•More structural parameters for phase and amplitude control than current nano-antennas.•Full phase control is achieved by designing rotation angle and structural parameters.•Allows metalens applications such as dual-focus in horizontal and vertical directions.•This design should help in developing precision optics for micro-object manipulation.