Superconducting kinetic inductance detectors will play an important role in the future of exoplanet spectroscopy. Their low bandgap and the possibillity that they can be multiplexed into large arrays open up new opportunities where conventional semiconductors stop. A key requirement for the performance of these new detectors is the consistency of their quality factor (Q-factor). Variations in Q-factors, known as Q-scatter, result in nonuniform sensitivity and hold back scaling to larger systems.

In this thesis, detectors that differ in fabrication, pixel count and pixel spacing are analyzed and compared to find out what is the cause of Q-scatter. Possible causes include design errors, inaccurate fabrication, electromagnetic crosstalk, magnetic vortices and unbalanced transmission lines. Analysis showed Q-scatter is unlikely to be impacted by design, fabrication method, electromagnetic coupling or vortex forming. Also, no spatial relations, that indicated any transmission line effects, were observed. What is interesting however, is that the Q-factors of one of the chips seem to scatter all over again when measuring the chip again after trimming one of its components.

With the data available in this experiment it was not possible to give an concrete cause of Q-scatter. Furhter experiments, especially concerning the new scattering need to be conducted. Also, simulations using Sonnet v19 can give more insights in the origin of Q-scatter.

In the mission of understanding the origins of life on earth and in the universe, astronomers are looking to exoplanets for signs of life. The spectra of light that has passed through an exoplanet's atmosphere is analysed for biomarkers. Until now most exoplanets have been found and characterised using the transit method. In the coming decade the aim is to look for planets using direct detection methods. In part for this purpose the European Extremely Large Telescope (EELT) is currently under construction and in future the Habitable World Observatory (HWO) is planned as a space-based telescope. To make full use of the EELT and the WHO extreme adaptive optics (XAO) systems using wave front sensors and deformable mirrors are needed. Contemporary CCD cameras utilizing semiconductor band gap energies are not sufficiently sensitive for wavefront sensing in direct exoplanet detection, let alone perform measurements to characterise their atmospheres. To this end different detectors are needed.

Kinetic inductance detectors (KIDs) are promising superconducting, energy resolving devices capable of single photon detection in the near-infrared and visible regimes. Another often cited advantage of KIDs is that, in theory, many detectors can easily be coupled to a single set of readout electronics. To make devices capable of producing images comparable to those achieved with CCDs we need a similar amount of pixels. The largest KID arrays to date are in the order of a thousand pixels on one readout line, whereas CCDs have in the order of millions of pixels. In this thesis some theoretical and practical limits on KID multiplexability while retaining high pixel yield are explored.