23 GHz operation of a room temperature photovoltaic quantum cascade detector at 5.35 <i>µ</i>m

We present a room temperature operated 5.35 <i>µ</i>m quantum cascade detector which was tested at high frequencies using an optical heterodyne experiment. Two slightly detuned continuous wave distributed feedback single mode quantum cascade lasers were used to generate a beating signal. The maximum frequency at which the resulting microwave signal could be detected was 23 GHz. The cutoff behavior of our device was modeled with a simple RLC circuit and showed excellent agreement with the experimental data.