High extinction ratio super pixel for long wavelength infrared polarization imaging detection based on plasmonic microcavity quantum well infrared photodetectors

Polarization imaging detection has its unique advantage in discriminating the man-made objects from natural objects. Grating integrated super pixel for polarization imaging detection can simultaneously obtain the first three elements of the Stokes vector, which is the trend of infrared polarization imaging detection in recent years. Here, we demonstrate the first super pixel for long wavelength infrared polarization imaging detection with the extinction ratio of its four polarization directions more than 100. The measured highest polarization extinction ratio is as high as 136, which is the highest reported value of long wavelength infrared polarization imaging detection super pixel. The mechanism is attributed to the excellent mode selectivity of plasmonic microcavity according to the results of three-dimensional theoretical simulation. The experimental responses of the super pixel with four polarization directions are in good agreement with the Malus' Law. In addition, the super pixel can accurately resolve the Stokes parameters at the same time. It is expected to develop the super pixel into a new generation of practical high-polarization-discriminating long wavelength infrared focal plane array.