Monolithically integrated Bragg reflectors to improve on the emitted power from metal-metal THz quantum cascade lasers

A metal-metal waveguide quantum cascade laser operating with a monolithically integrated Bragg reflector at ~ 2.9 THz is demonstrated. For a Bragg reflector spacing of λ₀/4 emission is suppressed to below that of a conventional device architecture; while as the spacing approaches λ₀/2 power increases. We observe an enhancement in emitted optical power by up to a factor of seven compared to a same sized device with no Bragg reflector.