title: Transient dual-energy lasing in a semiconductor microcavity.
abstract: We demonstrate sequential lasing at two well-separated energies in a highly photoexcited planar microcavity at room temperature. Two spatially overlapped lasing states with distinct polarization properties appear at energies more than 5 meV apart. Under a circularly polarized nonresonant 2 ps pulse excitation, a sub-10-ps transient circularly polarized high-energy (HE) state emerges within 10 ps after the pulse excitation. This HE state is followed by a pulsed state that lasts for 20-50 ps at a low energy (LE) state. The HE state is highly circularly polarized as a result of a spin-preserving stimulated process, while the LE state shows a significantly reduced circular polarization because of a diminishing spin imbalance.
authors.affiliation: Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Feng-Kuo
authors.initials: FK
authors.lastname: Hsu
authors.affiliation: Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Xie
authors.affiliation: Department of Electronics Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan.
authors.forename: Yi-Shan
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Department of Electronics Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan.
authors.forename: Sheng-Di
authors.initials: SD
authors.lastname: Lin
authors.affiliation: Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: Chih Wei
authors.initials: CW
authors.lastname: Lai