From fast light to slow light in resonantly driven quantum dot systems

In this article, we study the resonantly driven quantum dot systems. Based on the density matrix approach, we theoretically investigate the absorption and refractive index near the quantum dot resonance energy. We find that the systems show fast light effect at smaller incident light intensity due to the first order absorption, and show slow light effect at larger incident light intensity due to the third order absorption. It can be tuned by the incident light intensity, and be interpreted in terms of absorption saturation. It operates under normal environmental conditions and at telecommunication wavelengths, and may really be applied.