Bifocal and multifocal lenses allowing the incoming light to be focused at different focal spots can be applied in imaging, optical communication, and medical applications. In this study, we aim to solve the problems of multifocal lens design by using multilayer Pancharatnam-Berry (P-B) phase architecture. First, we will answer the fundamental question of what will happen when two layers of P-B phase elements are superimposed on each other. We show that a diffraction order with a phase shift equal to the rotation angle difference of the two layers can be observed. Based on this, we designed a multilayer metalens with arbitrary control of focal spot location and relative intensity.
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