temperature, and excitation power dependence Superfluorescence from photoexcited semiconductor quantum wells: Magnetic field

2015 American Physical Society. Superfluorescence (SF) is a many-body process in which a macroscopic polarization spontaneously builds up from an initially incoherent ensemble of excited dipoles and then cooperatively decays, producing a delayed pulse of coherent radiation. SF arising from electron-hole recombination has recently been observed in In0.2Ga0.8As/GaAs quantum wells [G. T. Noe, Nature Phys. 8, 219 (2012)1745-247310.1038/nphys2207 and J.-H. Kim, Sci. Rep. 3, 3283 (2013)2045-232210.1038/srep03283], but its observability conditions have not been fully established. Here, by performing magnetic field (B), temperature (T), and pump power (P) dependent studies of SF intensity, linewidth, and delay time through time-integrated and time-resolved magnetophotoluminescence spectroscopy, we have mapped out the B-T-P region in which SF is observable. In general, SF can be observed only at sufficiently low temperatures, sufficiently high magnetic fields, and sufficiently high laser powers with characteristic threshold behavior. We provide theoretical insights into these behaviors based primarily on considerations on how the growth rate of macroscopic coherence depends on these parameters. These results provide fundamental new insight into electron-hole SF, highlighting the importance of Coulomb interactions among photogenerated carriers as well as various scattering processes that are absent in SF phenomena in atomic and molecular systems.

Cong, Kankan||Wang, Yongrui||Kim, Ji-Hee||Noe, G Timothy II||McGill, Stephen A||Belyanin, Alexey||Kono, Junichiro

Superfluorescence from photoexcited semiconductor quantum wells: Magnetic field, temperature, and excitation power dependence Academic Article