Spontaneous parametric down-conversion is a non-linear optical process mediated by a crystal where an incident photon is converted into two or more outgoing photons. The theory describing...Show moreSpontaneous parametric down-conversion is a non-linear optical process mediated by a crystal where an incident photon is converted into two or more outgoing photons. The theory describing parametric down-conversion is studied; multi-photon correlations in a spatial basis and orbital angular momentum basis are studied theoretically and experimentally. For high intensity pump fields multiple photon pairs can be created. This is investigated experimentally and by simulation. Theory is developed to describe orbital angular momentum for multiple photon pairs and is applied to double photon pairs. Progress is made to differentiate between spontaneous and stimulated double photon pair emissions.Show less
We discuss our experimental efforts for generating and measuring four-photon entangled states, entangled in the orbital angular momentum space (OAM). For OAM space photons can be described in a...Show moreWe discuss our experimental efforts for generating and measuring four-photon entangled states, entangled in the orbital angular momentum space (OAM). For OAM space photons can be described in a high-dimensional Hilbert space. In order to generate the four-photon states, we use the process of spontaneous parametric down-conversion (SPDC) in a PPKTP crystal. Further a theoretical description on entangled states, Gaussian modes and SPDC is stated.Show less
Cluster states are a viable resource for quantum computing where information is stored in these states and one single-qubit measurement is performed at a time. In order to generate such states, we...Show moreCluster states are a viable resource for quantum computing where information is stored in these states and one single-qubit measurement is performed at a time. In order to generate such states, we use the quanta of light - photons - as our qubits. We generate them from a quantum dot in a microcavity which serves us as a deterministic single photon source. We explore a method of generating cluster states by entangling these photons with the means of linear optical elements and post-selection. We develop a theoretical model and show that it is in an agreement with our experimental data with single photons. From this agreement, we conclude that the cluster states arise in the experimental setup and the entanglement between the photons can be confirmed to be present with further analysis using our hypothesis and possibly even the quantum state tomography in the future.Show less
