Indirect—Band-Gap Super-Radiant Laser in GaP Containing Isoelectronic Traps

We report observations which can be interpreted as super-radiant laser emission in the indirect---band-gap semiconductor GaP. Optical gain, as high as 10⁴ cm^-1 at 2^∘{}K, has been measured over a range of temperatures from 2 to 300^∘{}K. The gain arises from a new process not important at low excitation intensities. It is demonstrated that isoelectronic traps are an important part of this new process.