| This dissertation aims at investigating the light-matter interactions between spins and photonic modes in semiconductor microcavities, as an understanding of these is an important prerequisite for possible applications in optical communications and for quantum information processing schemes. Single microdisks with GaAs quantum wells and natural quantum dots in the active region are characterized through both steady-state and time-resolved photoluminescence measurements at low temperatures. Using a pump-probe optical technique, the electron spin dynamics are investigated in the same structures and it is found that the spin coherence is enhanced on-resonance with the cavity and that this enhancement tracks the quality factor of cavity mode. This makes it possible to engineer this enhancement through careful design of the cavity, such as reducing the cavity size to improve the quality factor. These results motivated the extension to more complex structures, e.g. a pair of microdisks that are coupled through the evanescent electromagnetic field in order to take steps towards trying to utilize this spin-cavity interaction for transmitting information about spin states between cavities. Such coupled microdisks behave like "photonic molecules" with bonding and anti-bonding states and are examined in spatially-resolved and time-resolved luminescence measurements at low temperatures to try and understand dynamics of the carriers coupled to these extended cavity modes. Finally, single nitrogen-vacancy defects in diamond are investigated as a candidate material system for extending these studies of spins in cavities to room temperature. The nitrogen-vacancy shows strong spin-depenedent luminescence, even at room temperature and it is possible to study the interactions of its spin with other spins in its environment through optically-detected electron spin resonance measurements. In particular, studying the strong coupling between a single nitrogen-vacancy and a single electron spin of a substitutional nitrogen atom reveals that it is possible to polarize the nitrogen electronic spin via its magnetic dipolar coupling to the nitrogen-vacancy center spin, which is polarized by optically driving the nitrogen-vacancy transition. |
