Design and Characteristic Analysis of Off-Axis Meta-Lens

We propose a design method for off -axis meta -lens and analyze the effects of numerical aperture, off -axis angle, and incident wavelength on the simulation deviation, resolution and focusing efficiency of off-axis meta -lenses. Several off -axis meta -lenses with parameters NA=0.408 alpha=13 degrees, NA=0.180 alpha=13 degrees, NA=0.408 alpha=20 degrees were simulated by Lumerical, respectively. The simulation results indicate that the off -axis angle is directly proportional to the spectral resolution. As the angle increases, the spectral resolution becomes better, but the focusing efficiency decreases. A smaller numerical aperture result in a smaller coverage of the phase distribution, leading to a larger deviation between the simulation and theory. Designers need to reasonably balance parameters such as numerical aperture and off -axis angle according to the requirements to finally achieve the desired effect. This study has an important reference value for theoretical analysis and parameter design of off -axis meta -lens in practical application.