Optical linewidths in an individual quantum dot

On the basis of lattice relaxation due to the electron acoustic phonon coupling, we theoretically analyze the homogeneous optical linewidths of a single quantum dot. The calculated result based on a nonstrong-coupling approximation shows that in a considerable range of temperatures the homogeneous linewidth can be expressed in terms of Gamma(h) = Gamma(0) + AT, and the size dependence is characterized by Gamma(0) proportional to 1/R and A proportional to 1/R-2, where T is the temperature and R is the quantum dot radius. While this result qualitatively agrees well with the available experiments on exciton dephasing; it straightforwardly implies the infrared optical properties due to intraband transitions with transition energy around 100 meV.