Quantum dynamics of exciton lasers. A. İmamoğlu and R. J. Ram in Physics Letter A 214:193 (1996).  What the paper says!?

The Authors introduce the concept of an «exciton boser» (the name didn't stick) as an intermediate between a BEC and a laser, which they define as

a device that utilizes quantum statistical effects to generate a coherent population

of nonequilibrium excitons.

Although the paper is cited a lot for polariton lasing, the Authors explicitely rule out polaritons:

the prototype system that we envision is a GaAs quantum well at the node of a microcavity held. This configuration ensures that the relevant quasi-particles

are excitons rather than polaritons.

(they cite an unpublished work here). The picture they paint of the mechanism is, however, precisely that of the polariton laser:

An off-resonant circularly polarized optical pump creates free electron hole pairs which subse- quently form (optically inactive) excitons with large center-of-mass momentum k. These excitons decay by acoustic phonon emission to populate the k = 0 exci- tonic mode, where a population buildup occurs. The output from the exciton boser (coherent state of k = 0 excitons) is light generated by radiative recombi- nation. The emitted photons replicate the coherence

properties of the excitons