Highly Sensitive and Compact THz heterodyne receiver based on HEB and QCL at 2.7 THz

We present the development of a highly sensitive and compact HEB/QCL heterodyne detection system. The HEB mixer is a NbN nano-bridge mounted in an integrated lens-antenna configuration. The local oscillator is a low power consumption and low beam divergence 3rd order distributed feedback quantum cascade laser with single mode emission at the target frequency of 2.7 THz. A new quasi-optical coupling scheme between the mixer and the local oscillator has been developed that allows the removal of the beam splitter and therefore a better transmission of the RF signal and a more compact detection system. The lowest uncorrected double side band receiver noise temperature of this system is about 880 K.