| Popis: |
We present a high-speed quantum cascade detector (QCD), a mid-infrared photodetector using intersubband transition, with a frequency response of over 20 GHz. The frequency response of an uncooled QCD with the response wavelength of around 4.5 μm was evaluated with a heterodyne beat measurement using two distributed feedback single mode quantum cascade lasers, and -3 and -20 dB cut-off frequency was obtained to be 5 and 20 GHz. The maximum frequency observed in the experiment was 26 GHz with a signal-to-noise ratio of over 20 dB. These wide band mid-infrared photodetectors are expected to offer a high-speed molecular sensing, free-space optical communication, and the other applications. |
