Experimental investigation of low-frequency noise in quantum-cascade detectors

Frequency-dependent low-frequency noise in mid-infrared quantum cascade (QC) detectors, previously considered negligible, was experimentally investigated under the condition of high device resistance in which the Johnson-Nyquist noise is low. An excess noise increasing inverse-proportionally to the frequency was observed with clear dependences on the device size and temperature, and no dependence on the number of cascade modules. These experimental results exhibited qualitative agreement with a theoretical flicker noise model, which has been shown to explain the low-frequency noise in QC lasers well.