Independent electrical tuning of separated quantum dots in coupled photonic crystal cavities

Systems of photonic crystal cavities coupled to quantum dots are a promising architecture for quantum networking and quantum simulators. The ability to independently tune the frequencies of laterally separated quantum dots is a crucial component of such a scheme. Here, we demonstrate independent tuning of laterally separated quantum dots in photonic crystal cavities coupled by in-plane waveguides by implanting lines of protons which serve to electrically isolate different sections of a diode structure.Comment: 3 pages, 3 figure

Towards a Cost-Benefit-Analysis of Data-Driven Business Models

The emergence of data-driven business models calls for their systematic design and evaluation. In this paper, we focus on a first step towards a Cost-Benefit-Analysis of data-driven business models. Within data-driven business models, data act as enabler for the development of innovative services. However, to justify internal funding of new services, an assessment of the financial impact for the service at hand is often required. We approach this by identifying drivers of cost and benefit based on the Service Business Model Canvases of twenty cases. Based on the results, all drivers and their associated models for quantification were consolidated into a single meta-model. With this, we provide a basis for the economic assessment of service ideas and their refinement during the design process

Optical modes in oxide-apertured micropillar cavities

We present a detailed experimental characterization of the spectral and spatial structure of the confined optical modes for oxide-apertured micropillar cavities, showing good-quality Hermite-Gaussian profiles, easily mode-matched to external fields. We further derive a relation between the frequency splitting of the transverse modes and the expected Purcell factor. Finally, we describe a technique to retrieve the profile of the confining refractive index distribution from the spatial profiles of the modes.Comment: 4 pages, 3 figure

Tuning micropillar cavity birefringence by laser induced surface defects

We demonstrate a technique to tune the optical properties of micropillar cavities by creating small defects on the sample surface near the cavity region with an intense focused laser beam. Such defects modify strain in the structure, changing the birefringence in a controllable way. We apply the technique to make the fundamental cavity mode polarization-degenerate and to fine tune the overall mode frequencies, as needed for applications in quantum information science.Comment: RevTex, 7 pages, 4 figures (accepted for publication in Applied Physics Letters

Untersuchungen an carbenanalogen Imino- und Methylenphosphanen : Eigenschaften und Reaktionen

Ziel der vorliegenden Arbeit ist es, weitere Erkenntnisse über "carbenanaloge" Eigenschaften und Reaktionsmöglichkeiten von Methylen- und Iminophosphanen zu gewinnen. In diesem Zusammenhang interessiert das Reaktionsverhalten des Iminophosphans 1, das die erste Verbindung mit einer isolierten Phosphor-Stickstoff-π-Bindung darstellt und aufgrund seiner spektroskopischen Eigenschaften als Modellfall eines anorganischen Carbenanalogs anzusehen ist. Da aber entsprechende Reaktionsweisen von Methylenphosphanen bisher nichts bekannt ist, soll weiter festgestellt werden, ob durch geeignete Substitution Systeme erzeugt werden können, die eine carbenartige Grenzorbitalsequenz und eine dementsprechende Reaktivitat aufweisen. Darüberhinaus sollen Versuche zur Synthese und Reaktivität metallsubstituierter Phosphor-Stickstoff- und Phosphor Kohlenstoff-π-Bindungssysteme unternommen werden, bei denen infolge der hohen σ-Donorfähigkeit von Übergangsmetalliganden eine erhöhte Nukleophilie am Phosphor erwartet werden kann

CNOT and Bell-state analysis in the weak-coupling cavity QED regime

We propose an interface between the spin of a photon and the spin of an electron confined in a quantum dot embedded in a microcavity operating in the weak coupling regime. This interface, based on spin selective photon reflection from the cavity, can be used to construct a CNOT gate, a multi-photon entangler and a photonic Bell-state analyzer. Finally, we analyze experimental feasibility, concluding that the schemes can be implemented with current technology.Comment: 4 pages, 2 figure

Cavity quantum electrodynamics with quantum dots in microcavities

This thesis presents a viable route towards the implementation of quantum computing utilizing quantum dots embedded in optical microcavities. Following the introduction of the big picture and long-term visionary goal, general concepts fundamental to this field of research are described: quantum dots and microcavities, forming the physical system explored; and cavity quantum electrodynamics, the theoretical language used to describe their interaction. The physical structure and the optical mode composition in oxide-apertured micropillar cavities is analyzed. Permanent tuning methods achieving polarization degenerate cavities resonant with a quantum dot transition are illustrated. Active positioning of single quantum dots is developed providing an accuracy suitable to measure the interaction between a quantum dot and a cavity in the strong coupling limit. The possibility to waveguide-couple photonic crystal cavities on the same sample is explored. A theoretical description of the quantum-dot confined electron dynamics is presented. Presented are ideas how a hybrid quantum system could serve for implementation of a controlled NOT gate, and therewith be the building block for a quantum computer, exploiting the weak coupling regime. A Bell-state analyzer is the second scheme that is discussed. Results from reflection spectroscopy measurements on single quantum dots in a micropillar cavity are presented.LEI Universiteit LeidenQuantum Matter and Optic