Polarization selective uncooled infrared sensor using a one-dimensional plasmonic grating absorber

A polarization-selective uncooled infrared (IR) sensor has been developed based on a one-dimensional plasmonic grating absorber (1-D PGA). The 1-D PGA has an Au-based one-dimensional periodic grating structure, where photons can be manipulated by surface plasmon resonance. A microelectromechanical systems-based uncooled IR sensor was fabricated using the 1-D PGA with complementary metal oxide semiconductor (CMOS) and micromachining techniques. The 1-D PGA was formed with an Au layer sputtered on a grating pattered SiO2 layer. An Al layer was then introduced onto the backside of the 1-D PGA to reflect scattered light and prevent absorption at the SiO2 backside of the absorber. The responsivity could be selectively enhanced depending on the polarization and the grating direction, and an absorption wavelength longer than the surface period and broadband absorption were realized due to the effect of the resonance in the grating depth direction. The 1-D PGAs enable a detection wavelength longer than the period and broadband-polarization-selectivity by control of the grating depth in addition to the period. The results obtained in this study will contribute to the advancement of polarimetric IR imaging.