Broadband THz lasing from a photon-phonon quantum cascade structure emitting from 2.8 to 4.1 THz.

Laser emission over a broad range of frequencies from 2.8 to 4.1 THz is reported from a two-quantum well, photon-phonon cascade structure. Internal quantum efficiencies reaching 43% are evaluated at 10 K. Maximum operating temperatures of 125 K are reported, with peak optical powers in excess of 30 mW from a double-metal ridge waveguide. The laser operates in both polarities, showing laser action in reverse bias up to a temperature of 90 K.