Optical investigations of nanostructured oxides and semiconductors

This work is motivated by the prospect of building a quantum computer: a device that would allow physicists to explore quantum mechanics more deeply, and allow everyone else to keep their credit card numbers safe on the internet. In this thesis we explore materials that are relevant to a proposed quantum computer architecture.Systems with a ferroelectric to paraelectric transition in the vicinity of room temperature areuseful for devices. Adjusting the ferroelectric transition temperature is traditionally accomplished by chemical substitution, as in barium strontium titanate. We investigate strained-strontium titanate, which is ferroelectric at room-temperature, and a composite material of barium strontium titanate and magnesium oxide.We present optical techniques to measure electron spin dynamics with GHz dynamical bandwidth,transform-limited spectral selectivity, and phase-sensitive detection. We demonstrate the technique with a measurement of GHz-spin precession in n-GaAs. We also describe our efforts to measure single quantum dots optically.Nanoscale devices with photonic properties have been the subject of intense research over the past decade. Potential nanophotonic applications include communications, polarization-sensitive detectors, and solar power generation. Here we show photosensitivity of a nanoscale detectorwritten at the interface between two oxides