Multiwavelength metalens by spatial multiplexing at visible wavelengths

Abstract We theoretically demonstrate a multiwavelength metalens that operates concurrently at three visible wavelengths ( λ = 400, 600, and 800 nm). Multiwavelength metalenses are designed by a simple integration of metalens components by a spatial interleaving method (SIM) or by a symmetric linear array method (SLAM). The designed metalenses focus light to the same focal distance at three visible wavelengths with near diffraction-limited full width at half-maximum. At wavelengths of 400, 600, and 800 nm, the SIM metalens had focusing efficiencies of 32.6%, 43.6%, and 51.7%, respectively, and the SLAM metalens had focusing efficiencies of 35.6%, 43.8%, and 56.4%, respectively. These methods can provide a simple guideline to increase the operating wavelengths of metalenses.