Dephasing time characterization of InAs quantum dots by four-wave mixing measurement

We performed dephasing time characterization of InAs quantum dots waveguide and observed photon echo signal by time-resolved degenerate four-wave mixing. For large dots with a diameter of 40 nm, a relatively long T2 of330 f s was obtained. For small dots with a diameter of30 nm, a short T2 of230 f was obtained. Based on a comparison ofthe samples, it was suggested that this increase in T2 in large dots was due to the size dependence ofcarrier–LO phonon coupling. ? 2002 Elsevier Science B.V. All rights reserved.