The transmission and negative refractive index (NRI) of metal–dielectric–metal sandwiched metamaterials perforated with different filling media of holes are numerically studied. Results indicate that filling the appropriate medium in rectangular holes can
Freeform surfaces are increasingly used in the design of compact optical systems. Interferometric null test with computer generated hologram (CGH), which has been successfully used in highly accurate test of aspheric surfaces, is adopted to test the freef