Superchirality is a property of light with not yet fully discovered future possibilities in industry and research. In this research, an attempt to obtain a bright superchiral lattice is made by...Show moreSuperchirality is a property of light with not yet fully discovered future possibilities in industry and research. In this research, an attempt to obtain a bright superchiral lattice is made by superposing four laser beams in a particular configuration. Additionally, this superposition should theoretically lead to homogeneous electric fields without modulation, which is potentially useful in microscopy. Recording the field with a simple CMOS camera and observing its fast Fourier transform gives rise to aliasing effects due to undersampling caused by the fact that interference occurs at a subpixel level. This phenomenon is investigated by numeric and analytic simulations. By rotation of the camera, pixel superresolution was achieved, which effectively enables the possibility to investigate the interference patterns at a subpixel level and hence measure the angle between pair of beams with good accuracy. With newly developed beam alignment methods we have achieved and confirmed a beam alignment that is sufficient for production of bright superchirality lattices.Show less
Experimentally it has been found that a high power laser pulse focussed on a Helium gas at atmospheric pressure creates a plasma that over time assumes a torus shape. This process could see...Show moreExperimentally it has been found that a high power laser pulse focussed on a Helium gas at atmospheric pressure creates a plasma that over time assumes a torus shape. This process could see applications in plasma chemistry and is a first step towards a self-confined magnetohydrodynamics plasma. However, the torus shape is eventually destroyed as cold gas flow from the center of the torus splits the plasma. To study this process the gas dynamics shortly after the laser pulse are reduced to one dimension by applying cylindrical symmetry. The resulting equations are solved numerically. By fitting the one dimensional simulation results to experimental data, a three dimensional starting condition is proposed. Using this starting condition, a three dimensional axi-symmetric simulation is performed which is capable of reproducing both torus formation and splitting. These simulations show that the primary process responsible for torus formation is a low pressure area that is dragged behind the strong shock fronts moving perpendicular to the laser axis. Arguments for the local thermodynamic equilibrium of the plasma are presented. This justifies the application of the Saha equation to find the electron density from the simulated pressures and temperatures. Finally, passive modifications of the plasma environment are considered to prevent the plasma from splitting and provide flow confinement of the plasma for up to 100 μs.Show less
This thesis describes the development an easy to use, low cost device which can continuously measure the water transparency throughout different layers in ditches. The development of this device...Show moreThis thesis describes the development an easy to use, low cost device which can continuously measure the water transparency throughout different layers in ditches. The development of this device has started in several forms using several detection methods with LEDs, a laser or a pre-made turbidity sensor. The intended use of the device is in the ditches of the Living Lab in Leiden and might be expanded to ditches across the country. Another part of this thesis describes the development of an automatic air-based monitoring system for the Living Lab using a drone. The first steps towards the automation of this system have been made.Show less
In a quantum network, interconnected nodes use shared entangled states as a resource for communication. The nitrogen-vacancy (NV) centre in diamond is a promising candidate for the realization of a...Show moreIn a quantum network, interconnected nodes use shared entangled states as a resource for communication. The nitrogen-vacancy (NV) centre in diamond is a promising candidate for the realization of a such a node. It provides a solid state qubit that can be initialized and read out optically and manipulated via microwave pulses. However, for any practical implementation, control mechanisms that maintain the resonance of the excitation and emission frequencies need to be in place. Additionally, to guarantee phase stability as required for long distance entanglement, it is necessary to realize a frequency stabilized excitation laser. We demonstrate an autonomous routine for the optimization of excitation and emission frequencies, that recovers resonance conditions automatically when sudden jumps in the emission frequencies occur. Furthermore, an optical setup for the stabilization of excitation frequencies in a Pound-Drever-Hall scheme is presented. An upper bound on the excitation linewidth of 1.7 kHz is measured, yielding a phase deviation lower than 5 over a distance of 1 km. These developments will be essential in the development of a stand-alone quantum node involving the NV centre, on the road to a global quantum internet.Show less
