The abstract is not very clearly written. The 3.5 mV/cm is the maximum detectable field strength before the system starts to saturate. I would be interested how the sensitivity compares to conventional (cryogenic) semiconductor detectors.

Ah, yes, you are right, I misinterpreted the part the maximum was aimed at, thank you for the correction.

And I too am interested in a like-for-like setup with the best of what is currently on offer as the benchmark.