  It should be possible to improve hot-hole laser performance by moving from
bulk materials to a quantum well structure. The extra design parameters enable
us to alter the band structure by changing the crystal orientation of the
growth direction; to use the well width to shift the subband offsets, enabling
the effect of the LO phonon scattering cut-off to be controlled; and to use
modulation doping to ensure a high hole concentration to increase the gain
without the dopants being present in the gain region. We present the first
simulations of THz quantum well hot-hole lasers that can produce inversion and
optical gain.
