An array of polymer microlenses, made of 32×32 individual elements spaced by a 50-µm pitch, is used in connection to an array of 32×32 6-µm diameter SPADs (Single Photon Avalanche Detector), with the aim of mitigating the loss in sensitivity due to the area fill-factor. The lens array is fabricated by polymer casting in a photoresist replica mold. Results about repeatability of concentration factor and back focal length are reported. At C= 35 and a focal length F=40 µm, the spread of concentration is < 6%, and that of BFL is <0.5 µm.
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