Adjustable Triple Electromagnetically Induced Transparency and Kerr Nonlinearity in Five-Level Coupled Quantum Wells

In this article, we present an alternative excitation scheme for the study of optical responses of the probe field in a five-level semiconductor coupled quantum wells (CQWs). It is shown that in the linear case, our study reveals the formation of double and triple electromagnetically induced transparency (EIT) windows for the suitable values of Rabi-frequency of the control fields, while the linear dispersion is also tuned from anomalous to normal and vice versa within small range of detuning. Interestingly, we find that by properly adjusting the appropriate values of control field detunings, the behaviour of optical absorption and transparency is found to be asymmetric in nature. In addition, we also found that due to quantum coherence, nonlinear dispersion, specifically Kerr nonlinearity is dramatically enhanced with nearly vanishing linear absorption under EIT. The Kerr nonlinearity in the present scheme is identified to be very large (\(\:\sim{10}^{-13}\:{m}^{2}\:{V}^{-2}\)) in the mid IR range (\(\:{\lambda\:}_{p}=4.74\:\:\mu\:m\)), which can be very useful for the investigation of several nonlinear phenomena at low light intensity in CQWs. The results of the investigations may have potential applications in optical switching devices at low powers, quantum information processing and many more in solid-state laser based system.