  We show that superradiant emission (SR) in semiconductor laser diode
structures is governed by the master equation of the form of Ginzburg-Landau
equation or Gross-Pitaevskii equation for a phase transition to coherent matter
state. We conjectured condensation of one-dimensional longitudinal lower
polaritons with effective mass of 10$^{-11}$ the mass of free electron. Two
different regimes of SR emission and polariton condensation are predicted, one
of which exhibits some characteristic features of the Dicke superradiance in
atomic gases. The predictions of analytic model are confirmed by the results of
numerical simulations based on Maxwell-Bloch equations, utilizing InGaN/GaN
heterostructure quantum well as a model system.
