Particle swarm optimization-driven tomographic metalens for controllable super-resolution focusing

To address the limitations of traditional confocal microtomography, such as complex configuration, low integration, and poor stability, this study proposes a tomographic focusing metalens solution based on the particle swarm optimization (PSO) algorithm. By incorporating the phase compensation principle of the PSO algorithm, tomographic focusing imaging with controllable focal length, broadband compatibility, and high-resolution spectral performance is achieved within the visible wavelength range of 0.48-0.68 µm. The simulation results demonstrate that the metalens exhibits a tomographic scanning depth of 12.65 µm. Through PSO-enabled focal length presetting, the separation distance between adjacent focal points is precisely tunable. The lens achieves a maximum numerical aperture (NA) of 0.61, and the full width at half-maximum (FWHM) of each focal point is close to the diffraction limit. Notably, at a wavelength of 0.60 µm, the FWHM is even smaller than the diffraction limit, enabling ultra-high-resolution focusing imaging with quantum effects. This work holds broad application prospects in the field of tomographic imaging technology and provides a novel, to our knowledge, paradigm for the miniaturization and integration of computational photonics in imaging-related domains.