LAUSR

Interactions between excitons with different energies are significant in device application, particularly in the emission of intense terahertz (THz) waves caused by difference frequency mixing. In this paper, the interactions of excitons generated by two resonant continuous-wave laser beams are assessed via the change in reflectivity. While calculations suggest that the reflectivity change depends on the exciton number, experimental results measured for various excitation powers, probe powers, and excitation energies (heavy-hole (HH) and light-hole (LH) excitons) show different profiles. Furthermore, the signals probed at a HH exciton differ from those at a LH exciton. These results indicate the importance of careful control of excitation levels for THz wave generation.