Gain of excited states in the quantum-dots

In this work, we simulate the gain in the quantum-dot (QD) structures from the ground and excited states. This new model makes it possible to calculate gain from excited states in an easier manner where an inhomogeneous density of states is used with the probability functions taken from their rate equations. Effect of parameters like pumping level, intrinsic relaxation time (τ0) and temperature on the excited-state gain are examined. A comparison between thermal and nonthermal coupling is considered. It is found that longer τ0 is irrelevant for thermal coupling.