HUGE PHOTORESPONSE IN THE NONLOCAL TRANSPORT REGIME

We present experiments showing a significantly increased FIR photosens itivity of a high-mobility two-dimensional electron gas when transport in the quantum Hall regime is non-local, i.e. when scattering between adjacent edge channels is suppressed on macroscopic length scales. Th e resonant absorption under cyclotron resonance conditions enhances in teredge channel scattering processes leading to a huge resistance maxi mum in the longitudinal resistance and to the suppression of the non-l ocal resistance.