Fig. 2: Implementation of the photonic slide rule with metasurface.

a The metadevice comprises interleaved metaatoms of Group A and Group B, which generate two opposite phase vortices driven by the incident frequency. The linear plots along the phase annuluses are illustrated. The interference holography generates a moving symmetric annulus with intensity distribution indicated as the purple curve on the right. As a representative, intensity distribution at wavelength 3.75 μm is for demonstration. b The metadevice design can be decoupled to two parts: vortex generation and achromatic annular focusing. Both phase profiles are dependent on the frequency. In the vortex beam design, the phases rotate in opposite directions and at distinct angular velocities with different topological charges. The achromatic annular focusing design allows the enhanced intensity distributions and ensures the confocal spots at different frequencies. c Schematic of the metaatom made in a pure silicon wafer. The metaatom period is 1.7 μm, and the height is 7 μm. The width w, length l, and rotation angle θ are swept to construct the phase and dispersion control database. d The group delay coverages of the Group A and Group B metaatoms selected from the metaatom database. The data number represents the metaatom number with filtering criteria in the achromatic design of Supplementary Note 2.