Exciton and photon dynamics in nanostructures

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The proposed research is to theoretically and computationally investigate the behaviour of electrons and photons in semiconductor nanostructures on very short time scales. Semiconductor nanostructures are semiconductors that are structured on length scales ranging from one billionth to 500 billionths of a metre. The confinement of the electrons in such structures results in quantum mechanical effects similar to those that cause the energy-level quantization in an atom. The reflections of the photons at interfaces in nanostructures called photonic crystals can trap the photons, resulting in large changes in the photon-electron interactions. As a result of these confinement effects, the optical and electrical properties of nanostructures are very different from those of the constituent materials. I will primarily focus on semiconductor superlattices, quantum wells, quantum dots and photonic crystals. For these structures, I will develop theoretical and computational models of 1) The ultra-fast dynamics of nanostructure excitons set into motion by ultra-short laser pulses (~0.0000000000001 seconds long) and 2) The dynamics of photons and excitons in semiconductor photonic crystals. Excitons are particles in semiconductors that consist of an excited electron bound to the "hole" that is left behind when the electron is excited; they play a central role in the optical response of the semiconductors. The models developed will predict the properties of the light emitted from and absorbed by the nanostructures. This research will expand the knowledge of the behaviour of nanostructure excitons and photons. It will also help improve the design of optoelectronic devices such as lasers, optical switches, and optical amplifiers that are at the heart of information technology. Part of the research is aimed at modelling and designing a new type of tuneable solidstate Terahertz laser, which emits light that lies between the microwave and infrared portions of the electromagnetic spectrum. Another topic is to improve the design of vertical cavity surface emitting lasers based on photonic crystal slabs. Finally, part of my work will aid in the development of entirely new quantum information processing devices.