Wavelength-dependent multifunctional metalens devices via genetic optimization

Metalenses with non-trivial performance, abundant applications, and tremendous potential, have emerged as a flat optical element or configuration in recent years. The increasing concerns about how to integrate more functions into a single metalens have become a hot topic. Here, based on a genetic algorithm, we demonstrate several metalenses with more than two optical functions depending on the wavelength of light. We first design three arbitrary chromatic dispersive metalenses, whose focal planes can be determined at will at different wavelengths. Then, a metalens-based color router is presented, which is able to guide and focus the light with four wavelengths to different positions. Furthermore, we exhibit a tri-functional structured light generator to produce focused beam, focused orbital angular momentum beam, and the Besse' beam at three wavelengths, respectively. Our results may have potential applications in dispersion manipulation, optical micro-manipulation, and subwavelength resolution spectral imaging. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement