Integrated spectral-polarization imaging sensor with aluminum nanowire polarization filters

Current division-of-focal-plane polarization imaging sensors can perceive intensity and polarization in real time with high spatial resolution, but are oblivious to spectral information. We present the design of such a sensor, which is also spectrally selective in the visible regime. We describe its extensive spectral and polarimetric characterization. The sensor has a pixel pitch of 5 µm and an imaging array of 168 by 256 elements. Each element comprises spectrally sensitive vertically stacked photodetectors integrated with a 140 nm pitch nanowire linear polarizer. The sensor has a maximum measured SNR of 45 dB, extinction ratio of ~3.5, QE of 12%, and linearity error of 1% in the green channel. We present sample spectral-polarization images.