Abstract 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 (
∼10−13m2V−2) in the mid IR range (
λp=4.74μm), 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.
We report a new all-optical switching in a two-dimensional photonic crystal microcavity made of semiconductor multiple quantum wells and realized based on the electromagnetically induced transparency effect with exciton and two-exciton energy levels. We use the quantum coherence effects to achieve small absorption of the probe field, and the absorption of the probe field can be adjusted by controlling the pump field and decay rate. We turn the control field into pulses of light field so that we can regulate the efficiency of the switch. Through selecting the appropriate control light field intensity, we can obtain a switching efficiency of 85% and a switching time is 10 ps. This result can be used for the development of new types of nanoelectronic devices for realizing the switching process.