Inversion Design of Ultraviolet Achromatic Metalenses Based on Particle Swarm Optimization Algorithm

This paper employs a heuristic algorithm, specifically the Particle Swarm Optimization (PSO), to perform inverse design of metalenses in the ultraviolet spectrum, achieving chromatic aberration correction over a broad wavelength range of 300-400 nm. Initially, the study focuses on the construction of silicon nitride (Si<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>N<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf>) nano-pillars on a silicon nitride substrate. Numerical simulation software is utilized to scan the length and width of these nano-pillars, thereby establishing a phase database. Subsequently, the PSO is applied to identify the optimal meta-atoms within the phase database that meet the phase requirements for a wide wavelength range. Finally, the metalens is constructed, and numerical simulation is used to realize an achromatic metalens in the 300-400 nm wavelength band. This work provides a methodological approach for the inverse design of achromatic metalenses in the ultraviolet spectrum.