Metalens with corrected phase

A computer-implemented method for designing a metalens having a metasurface including nano-structures arranged on a substrate based on preliminary simulation data, wherein the method uses a processor coupled with a memory storing a target near field profile, the preliminary simulation data of the metalens and instructions implementing the method, wherein the preliminary simulation data represent design parameters including geometry and orientation angle with respect to the nano-structures on the metalens, wherein the instructions, when executed by the processor, carry out at steps of the method, comprising:

• partitioning the nano-structures into overlapping d-unit supercells such that every non-perimeter nano-structure is at a center of one d-unit supercell;
• computing a differentiable mapping function of the d-unit supercells that predicts the near-field over the unit cell at the center of the supercell from the design parameters of all the nanostructures in the supercell, by fitting an interpolator to preliminary simulation data of the d-unit supercells;
• jointly tuning the design parameters of all unit cells in the metalens to better approximate a target near field distribution over the entire metalens, by using a Jacobian of partial derivatives provided by the mapping function to solve for a locally optimal correction of all design parameters;
• and
• generating a fabricable design of the metalens based on the optimized parameters.