Metasurface-assisted amorphous germanium-tin waveguide bolometer for mid-infrared photodetection

An amorphous germanium-tin (a-Ge 0.83 Sn 0.17 ) waveguide bolometer featuring a one-dimension (1D) metasurface absorber is proposed for mid-infrared photodetection at room-temperature. The device is based on the germanium-on-silicon (GOS) photonic platform. The impacts of the 1D metasurface on the performances of the waveguide bolometer are investigated. The responsivity of the a-Ge 0.83 Sn 0.17 waveguide bolometer could be significantly enhanced by the metasurface. A responsivity of around −3.17%/µW within the 4.1 ∼ 4.3 µm wavelength range is achieved. In addition, a 3-dB roll-off frequency higher than 10 kHz is obtained.