Quantum memory devices and scalable quantum computers are important objectives of current research efforts. Quantum computers promise to solve certain problems which are intractable on classical computers and may provide insight into unanswered questions in computational theory. Quantum memory would provide coherent storage of a 'qubit' and could be used in conjunction with a quantum computer or in a quantum communication system. Both systems require a way of preparing qubits in a known state, a mechanism for measuring their states and addressing capability. Nuclear spins within a solid-state system have been proposed as one means for realizing a quantum computer. The preparation of nuclear spins in a known state and qubit readout remain a formidable challenge. Quantum dots provide a means of polarizing and measuring nuclear spins. We have observed the energy level shifts due to the nuclear spins in InAs quantum dots and we have measured the timescale for nuclear polarization to develop.; Quantum dots are nano-scale regions of a small band-gap semiconductor embedded in a larger band-gap semiconductor which can trap a single electron-hole pair or exciton. The energy levels for the exciton are quantized and are affected by many parameters including hyperfine interactions with the nuclei from the lattice. There are between 104 and 105 nuclei within the dot and it is possible through optical pumping to align the nuclear spins in one direction. We can also use the interaction of the nuclear spins with the exciton to determine the average nuclear spin direction. Future work in this area may ultimately lead to useful applications for nuclear spins in the area of quantum information processing devices.; In this thesis I will present results demonstrating nuclear polarization in InAs quantum dots. In addition, I will present background material and experimental details with the basic goal that a reader of this thesis could reproduce the results we have obtained. There is also a theoretical discussion in which I present a model for the nuclear polarization process and compare the predicted timescales to the measured results. I will also discuss work I carried out using sculpted ferromagnets with the goal of creating large magnetic field gradients. Such devices could be used in conjunction with quantum clots in order to do atomic plane imaging as discussed in Chapter 9. Chapter 4 provides a background to the discussion regarding magnetic field gradient calculations.
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