Real-Time Analysis of THz Quantum-Cascade Laser Signals using a Field Effect Transistor Array

We demonstrate real-time analysis of the emission from a 3.4-THz quantum-cascade laser (QCL) source, using an array of nanoscale field-effect transistor devices. We show that THz power can be detected directly up to a modulation bandwidth of 500 kHz, and indirectly via a change in the device threshold, up to a 100-MHz bandwidth.