An imaging device including a plurality of photo-sensitive elements suitable for imaging small objects less than 500 nm in size. Each of the photo-sentive elements forms a passive pixel which comprises at least one nanowire structured photodetector and a switch transistor. The nanowire structured photodetector is configured to receive the photons and store the photo generated charges and behave as a waveguide. The switch transistor is formed either in the substrate or at the same body of the nanowire and is configured to allow photo-genereated charges in the nanowire to accumulate when off and to drain from the nanowire when on. The pixel array is configured to allow high resolution imaging by arranging in a penny round pattern.