Planar immersion lens with metasurfaces

A planar immersion lens configured to focus electromagnetic radiation from an incident medium into a refractive medium, comprising:

• a substrate;
• a plurality of metallic elements disposed on the substrate, wherein adjacent metallic elements are separated by a sub-wavelength distance;
• and
• a plurality of passive elements disposed on the plurality of metallic elements;
• the planar immersion lens being configured to impart a phase profile on an incident electromagnetic wave passing across the planar immersion lens to focus the incident electromagnetic wave across an air-gap between the planar immersion lens and the refractive medium with wave components at or beyond a critical angle.

A wireless power transfer system, comprising:

• a planar immersion lens configured to focus electromagnetic radiation from an incident medium into a refractive medium, the planar immersion lens having:
• a substrate;
• a plurality of metallic elements disposed on the substrate, wherein adjacent metallic elements are separated by a sub-wavelength distance;
• and
• a plurality of passive elements disposed on the plurality of metallic elements;
• the planar immersion lens being configured to impart a phase gradient on an incident electromagnetic wave passing across the planar immersion lens to focus the incident electromagnetic wave across an air-gap between the planar immersion lens and the refractive medium at or beyond a critical angle;
• and
• a wireless power receiver comprising an energy harvesting structure, the wireless power receiver being configured to receive the focused electromagnetic wave from the planar immersion lens with the energy harvesting structure to generate power in the wireless power receiver.