On-chip THz generation and detection at milli-Kelvin temperatures for the study of ultrafast phenomena in confined semiconductor systems

We present a new measurement technique for the sub-Kelvin excitation and detection of on-chip terahertz frequency radiation in high magnetic fields. We present a monolithically integrated heterostructure, which allows a mesoscopic electronic system to be combined with an on-chip terahertz device, and show dynamic imaging of a THz photoconductive switch at 200 mK in a 12 T field, together with THz signal propagation at 100 mK. These capabilities will advance significantly the study of ultrafast phenomena in mesoscopic semiconductor systems.