Fig. 3: Bias-switch dual-band detection.
a Relative response spectrum with polarization resolution of the mid-wavelength infrared (MWIR) photodetector. The blue solid line and dashed line are polarized incident light incident along the AC direction and ZZ direction of bP, respectively. The red solid line and dashed line are polarized incident light incident along the AC direction and ZZ direction of b-AsP, respectively. b I–V curves of the photodetector in the dark and under 500 °C blackbody radiation illumination. c Frequency response of MWIR1 channel and MWIR2 channel to 1550 nm modulated laser. Vd is the bias voltage and f-3dB is the frequency at −3dB point. d Photoresponse of MWIR1 channel and MWIR2 channel to the blackbody radiation respectively. e Left axis, MWIR1 and MWIR2 signal as a function of detection distance. Right axis, the relationship between the MWIR2/MWIR1 ratio and detection distance. The horizontal black dashed line is the fitting line. f Summary of the MWIR2/MWIR1 ratio depends on the temperature of the detected target. Red dots show the measured MWIR2/MWIR1 ratio as a function of blackbody temperature and the pink dashed line is the fitting curve.
