Advances in metasurface-based mosaic filters for single-photon detector arrays

This paper introduces the field of metamaterials, details various optical uses of metasurfaces and demonstrates their suitability for imaging with single-photon avalanche diode (SPAD) detector arrays as an integrated optical component. A design for a metasurface-based color filter array (CFA) is presented, the fabrication methodology detailed, and a sample is integrated with a SPAD array. Examples of imaging applications using the integrated assembly are demonstrated, including passive and fluorescence imaging microscopy. The limitations of current metasurface color filtering techniques are highlighted and directions for future advances and applications discussed.