Lossless imaging based on a donut-like optical sparse aperture metalens

The optical sparse aperture approach has been shown to have significant potential in enlarging the aperture size and enhancing the imaging resolution of metalenses. However, because of frequency loss caused by the sparsity and dispersion of sparse aperture arrays, the stitch method for conventional optical sparse aperture metalenses has a non-uniform imaging resolution at different azimuth angles and cannot achieve the same resolution as the corresponding full-aperture metalens. Here, we design and demonstrate the application of a donut-like optical sparse aperture metalens with a lossless imaging property using a shear design method. This metalens has a diffraction-limited resolution of 153 lp/mm for all azimuth angles, which allows us to circumvent the non-uniform imaging resolution of the conventional optical sparse aperture metalens at different azimuth angles and enables us to achieve full resolution. Furthermore, noise resistance in practical images is achieved because of the improved modulation transfer function in the high-frequency region. Such a metalens without frequency loss has significant application potential in the fields of integrated optical systems, lightweight imaging devices, and wearable optics.