High frequency measurements on an AlN/GaN-based intersubband detector at 1550 and 780 nm

We report on high frequency measurements on an AlN/GaN-based intersubband detector using mode-locked solid state lasers. Our experiments involving laser wavelengths of 1550 and 780 nm demonstrate not only the capability of such devices to work both at the fundamental and at a higher order intersubband transition, but they also allowed us to push the high frequency detection limit up to a value of 13.3 GHz. From the shape of the harmonic decay, we conclude that this limit is not due to intrinsic properties of the detector.