For a system of coplanar electrons and holes the photoluminescence spectrum in the fractional quantum Hall regime does not exhibit anomalies associated with the fractional quantum hall effect. However, when electron and hole layers are separated, a new peak in the photoluminescence spectrum is introduced when the filling factor exceeds a fraction ${\nu }_0$ at which an cincompressible state occurs. The new peak is separated from the main spectral feature by the quasiparticle-quasihole gap and corresponds to a process in which a fractionally charged quasiparticle recombines with a hole, leaving behind fractionally charged quasiholes.

• Received 2 December 1991

DOI:https://doi.org/10.1103/PhysRevLett.68.1939