Response to Room Temperature, Quantum-Limited THz Heterodyne Detection? Not Yet

This commentary is written in response to arXiv:1907.13198. In this article, Zmuidzinas et al. raise questions about the results reported by our group in Nature Astronomy (DOI: 10.1038/s41550-019-0828-6) regarding our experimental methodology and our device performance metrics. As described in this Response, Zmuidzinas et al. have unfortunately missed some basic principles on impedance matching and the physics of photomixers and plasmonics that are at the heart of their categorical conclusions. Here, we correct these misunderstandings and discharge all of their flawed conclusions. Therefore, all of the results and conclusions reported in our Nature Astronomy manuscript remain correct, as before.