Exciton-population inversion and terahertz gain in semiconductors excited to resonance.
The buildup of exciton populations in resonantly laser excited semiconductors is studied microscopically. For excitation around the 2s-exciton resonance, it is shown that polarization with a strict s-type radial symmetry can be efficiently converted into an incoherent p-type population. As a consequence, inversion between the 2p and 1s exciton states can be obtained leading to the appearance of significant terahertz gain.
Fachbereich Physik and Material Sciences Center, Philipps Universität, Renthof 5, 35032 Marburg, Germany.
M
M
Kira
S W
SW
Koch