Multifocal co-plane metalens based on computer-generated holography for multiple visible wavelengths

•Computer-generated holography method using Fresnel diffraction provides a simple method for calculating the phase distribution and design the multifocal metalens.•All-dielectric materials structure are adopted to improve transmission efficiency.•The maximum value of focusing efficiency of the proposed metalens can reach 92%.•Single metalens and multifocal metalenses have a good broadband performance and break optical diffraction limit.