Impact of interactions with the environment on the quantum optical response of individual quantum dots

Transferring information encoded in optical signals has revolutionized the telecommunication industry in the 20th century and fundamentally changed the interaction between people. Using optical and digital information protocols, data transfer rates rising up to speeds as fast as 1 Peta-bit per second per kilometer have been realized. Nevertheless, even for state-of-the-art telecommunication systems, the two essential components remain a transmitter and a receiver that build the interface between optical signals and solid-state memories or logic elements to store and decode the transferred information. The development of efficient optical transmitters and receivers naturally requires a detailed understanding of light-matter interfaces and photonic engineering. For classical optically based communication protocols information is encoded digitally in optical pulses containing millions of photons and research currently focuses on advancing these concepts to an ultimately efficient information transfer and storage. At the quantum limit, where one bit of information is stored per particle, classical concepts and digital algorithms fail as the interaction between single particles is governed by quantum mechanics. Progress to the quantum limit of communication and information processing promises a second revolution in modern communication. However, advancing the classical receivers to quantum receivers and classical transmitters to quantum transmitters in telecommunication, demands a profound understanding of the non-classical effects of light-matter interactions of solid-state systems. This thesis investigates non-classical effects emerging at the optical interface of single particles in semiconductors with a coherent optical control field. To this end, the investigation focuses on single quantum states localized in optically active quantum dots hosted in a solid state environment made of III-V compound semiconductors. Qubits working as a quantum memory have been implemented as single spins and excitons and such systems can be optically initialized, controlled and readout. However, since these systems are strongly coupled to their solid-state host environment, the quantum physics governing the non-classical light-matter interaction of these semiconductor systems deviate away from the canonical example of an isolated atomic few-level system interacting with a coherent light field.