An image sensor includes a multi-pixel detector. The multi-pixel detector includes a first pixel formed in a substrate and having a first photodiode region, a second pixel formed in the substrate adjacent to the first pixel and having a second photodiode region, and a microlens above both the first pixel and the second pixel. The microlens includes (a) in a first cross-sectional plane perpendicular to a top surface of the substrate and including both the first and the second photodiode regions, a first height profile having N1 local maxima, and (b) in a second cross-sectional plane perpendicular to the first cross-sectional plane and the top surface and including only one of the first and the second photodiode regions, a second height profile having N2>N1 local maxima.