Optimization and experimental validation of a bi-focal lens in the microwave domain

The design of photonic devices is usually done through analytical modeling or variation in geometry and material parameters to obtain the required functionalities. Here, we report use topology optimization a bi-focal lens that concentrates electromagnetic field at different spatial positions depending on wavelength. Numerical inverse carried out permittivity layout, satisfying this objective. resulting device then 3D printed using two low-loss dielectrics, experimental mapping microwaves demonstrates ability enhance locally distinct locations for separate frequencies.