All-dielectric resonant waveguide based quantum well infrared photodetectors for hyperspectral detection

All-dielectric resonant waveguide based quantum well infrared photodetectors with high responsivity, fine spectral resolution and a wide spectral range are proposed. Without ohmic loss, the guided mode resonances lead to highly efficient absorption of the field power by the quantum wells and high Q factors for narrow spectral widths. Close to 100% resonant absorption with spectral resolution finer than 100 nm could be achieved in the long wavelength infrared region. When the incident wavelengths deviate from the intrinsic absorption range of the quantum wells, a decrease in absorption coefficient causes an increase in Q factor and in mode intensity that would compensate the absorption power. As a result, a three-fold extension of the absorption range is demonstrated. The infrared detectors with these advances simultaneously are well suited for hyperspectral detection. Further, the device could be either polarization discriminative or insensitive by using anisotropic or isotropic in-couple gratings. The good tolerance to structural deviation could facilitate the fabrication process.