We demonstrate a semiconductor plasmonic hot carrier detector in the mid-infared which uses the well-known Berreman mode (a volume plasmon in a slab thinner than the plasma wavelength) as the absorbing medium. We demonstrate the same device can be used to emit light at the plasma frequency via excitation by a pulsed electrical current. Our system is an ideal platform to study the long-standing problem of the interaction of a single particle current with a collective electronic excitation.